I generated a new map and then saved it as a seed map. Deciding to start on it, I loaded it and got the following error:
Error while running event UsefulCombinators::on_tick (ID 0)
UsefulCombinators/control.lua:1040: bad argument #1 to 'pairs' (table expected, got nil)

Will look into it.

From what I've seen from my own testing, as long as you have at least one useful combinator combinator (ergo a combinator from this mod pack placed) the save will load without any issue, but if you have yet to place one, the mod will throw that error.

Hmm... Strange... That line (1040) should, in no way, cause an error, yet you managed to make it cause one.

Could you list the steps to reproduce the error?

Start the game, load up a new map, save the map, load map, crash.
I can post the mod list I'm using if that might help.

Please post mod list as I am unable to reproduce the bug

0.502 Loading mod core 0.0.0 (data.lua)
0.507 Loading mod base 0.15.23 (data.lua)
0.582 Loading mod FARL 1.1.2 (data.lua)
0.597 Loading mod TogglePeacefulMode 0.1.1 (data.lua)
0.610 Loading mod what-is-it-really-used-for 1.2.5 (data.lua)
0.624 Loading mod autofill 1.4.8 (data.lua)
0.637 Loading mod beltSorter 0.4.1 (data.lua)
0.653 Loading mod Big_Brother_Tweaked 0.4.2 (data.lua)
0.678 Loading mod bobinserters 0.15.1 (data.lua)
0.693 Loading mod boblibrary 0.15.8 (data.lua)
0.710 Loading mod botReplacer 0.15.0 (data.lua)
0.726 Loading mod Bottleneck 0.8.5 (data.lua)
0.742 Loading mod bullet-trails 0.2.4 (data.lua)
0.757 Loading mod Crafting_Speed_Research 0.1.5 (data.lua)
0.772 Loading mod even-distribution 0.2.4 (data.lua)
0.788 Loading mod EvoGUI 0.4.205 (data.lua)
0.806 Loading mod HandyHands 1.5.1 (data.lua)
0.822 Loading mod helmod 0.5.7 (data.lua)
0.840 Loading mod LR_Turret 0.15.0 (data.lua)
0.857 Loading mod MapLabels 0.15.5 (data.lua)
0.873 Loading mod Miner_Planner 0.9.9 (data.lua)
0.889 Loading mod Nanobots 1.8.2 (data.lua)
0.908 Loading mod Nuclear Fuel 0.1.0 (data.lua)
0.926 Loading mod ore-eraser 1.4.0 (data.lua)
0.943 Loading mod Side Inserters 2.3.3 (data.lua)
0.960 Loading mod textplates 0.2.5 (data.lua)
0.983 Loading mod Warehousing v15 0.0.13 (data.lua)
1.006 Loading mod water-fix 0.2.1 (data.lua)
1.037 Loading mod YARM 0.7.203 (data.lua)
1.059 Loading mod alien-biomes 0.2.7 (data.lua)
1.092 Loading mod bobores 0.15.6 (data.lua)
1.117 Loading mod bobtech 0.15.3 (data.lua)
1.142 Loading mod bobvehicleequipment 0.15.2 (data.lua)
1.170 Loading mod crafting_combinator 0.9.4 (data.lua)
1.199 Loading mod PickerExtended 2.8.1 (data.lua)
1.232 Loading mod bobplates 0.15.11 (data.lua)
1.265 Loading mod rso-mod 3.3.9 (data.lua)
1.293 Loading mod angelsrefining 0.7.16 (data.lua)
1.331 Loading mod bobassembly 0.15.6 (data.lua)
1.366 Loading mod bobelectronics 0.15.2 (data.lua)
1.398 Loading mod bobgreenhouse 0.15.2 (data.lua)
1.431 Loading mod boblogistics 0.15.6 (data.lua)
1.479 Loading mod bobmining 0.15.2 (data.lua)
1.523 Loading mod bobpower 0.15.3 (data.lua)
1.568 Loading mod bobrevamp 0.15.4 (data.lua)
1.609 Loading mod BurnCycle 1.0.0 (data.lua)
1.651 Loading mod angelsaddons-oresilos 0.3.1 (data.lua)
1.698 Loading mod angelsaddons-warehouses 0.2.1 (data.lua)
1.742 Loading mod angelscomponents 0.2.0 (data.lua)
1.787 Loading mod angelspetrochem 0.5.10 (data.lua)
1.844 Loading mod Arborium 0.15.1 (data.lua)
1.892 Loading mod bobmodules 0.15.3 (data.lua)
1.945 Loading mod bobwarfare 0.15.3 (data.lua)
2.005 Loading mod LoaderRedux 1.1.1 (data.lua)
2.056 Loading mod angelsexploration 0.2.0 (data.lua)
2.108 Loading mod angelsinfiniteores 0.6.11 (data.lua)
2.162 Loading mod angelslogistics 0.2.0 (data.lua)
2.217 Loading mod angelssmelting 0.3.3 (data.lua)
2.284 Loading mod research-queue 1.5.1 (data.lua)
2.341 Loading mod angelssmelting-extended 0.0.3 (data.lua)
2.407 Loading mod GDIW 0.15.2 (data.lua)
2.466 Loading mod only-smelting 0.1.2 (data.lua)
2.526 Loading mod GDIWHotkey 1.1.0 (data.lua)
2.585 Loading mod base 0.15.23 (data-updates.lua)
2.652 Loading mod FARL 1.1.2 (data-updates.lua)
2.715 Loading mod Big_Brother_Tweaked 0.4.2 (data-updates.lua)
2.778 Loading mod bobinserters 0.15.1 (data-updates.lua)
2.841 Loading mod bullet-trails 0.2.4 (data-updates.lua)
2.904 Loading mod folk-stopthat 0.1.2 (data-updates.lua)
2.968 Loading mod Nanobots 1.8.2 (data-updates.lua)
3.032 Loading mod ShinyAngelGFX 0.15.1 (data-updates.lua)
3.098 Loading mod Side Inserters 2.3.3 (data-updates.lua)
3.164 Loading mod Squeak Through 1.1.7 (data-updates.lua)
3.226 Loading mod alien-biomes 0.2.7 (data-updates.lua)
3.291 Loading mod bobores 0.15.6 (data-updates.lua)
3.356 Loading mod bobtech 0.15.3 (data-updates.lua)
3.421 Loading mod bobvehicleequipment 0.15.2 (data-updates.lua)
3.487 Loading mod crafting_combinator 0.9.4 (data-updates.lua)
3.551 Loading mod PickerExtended 2.8.1 (data-updates.lua)
3.615 Loading mod bobplates 0.15.11 (data-updates.lua)
3.683 Loading mod rso-mod 3.3.9 (data-updates.lua)
3.748 Loading mod angelsrefining 0.7.16 (data-updates.lua)
3.823 Loading mod bobassembly 0.15.6 (data-updates.lua)
3.890 Loading mod bobelectronics 0.15.2 (data-updates.lua)
3.956 Loading mod bobgreenhouse 0.15.2 (data-updates.lua)
4.022 Loading mod boblogistics 0.15.6 (data-updates.lua)
4.090 Loading mod bobmining 0.15.2 (data-updates.lua)
4.156 Loading mod bobpower 0.15.3 (data-updates.lua)
4.224 Loading mod bobrevamp 0.15.4 (data-updates.lua)
4.291 Loading mod angelsaddons-oresilos 0.3.1 (data-updates.lua)
4.357 Loading mod angelsaddons-warehouses 0.2.1 (data-updates.lua)
4.423 Loading mod angelspetrochem 0.5.10 (data-updates.lua)
4.500 Loading mod Arborium 0.15.1 (data-updates.lua)
4.569 Loading mod bobmodules 0.15.3 (data-updates.lua)
4.641 Loading mod bobwarfare 0.15.3 (data-updates.lua)
4.714 Loading mod angelsexploration 0.2.0 (data-updates.lua)
4.783 Loading mod angelslogistics 0.2.0 (data-updates.lua)
4.869 Loading mod angelssmelting 0.3.3 (data-updates.lua)
4.954 Loading mod bobmods_gfxtweak 0.15.3 (data-updates.lua)
5.035 Loading mod FARL 1.1.2 (data-final-fixes.lua)
5.110 Loading mod detached-gun-sounds 0.2.1 (data-final-fixes.lua)
5.180 Loading mod even-distribution 0.2.4 (data-final-fixes.lua)
5.250 Loading mod helmod 0.5.7 (data-final-fixes.lua)
5.331 Loading mod Nanobots 1.8.2 (data-final-fixes.lua)
5.401 Loading mod off-grid-effects 0.2.2 (data-final-fixes.lua)
5.471 Loading mod tree_collision 0.4.1 (data-final-fixes.lua)
5.541 Loading mod walls-block-spitters 0.2.3 (data-final-fixes.lua)
5.612 Loading mod crafting_combinator 0.9.4 (data-final-fixes.lua)
5.692 Loading mod PickerExtended 2.8.1 (data-final-fixes.lua)
5.766 Loading mod bobelectronics 0.15.2 (data-final-fixes.lua)
5.872 Loading mod angelspetrochem 0.5.10 (data-final-fixes.lua)
5.952 Loading mod angelsinfiniteores 0.6.11 (data-final-fixes.lua)
6.026 Loading mod angelslogistics 0.2.0 (data-final-fixes.lua)
6.100 Loading mod angelssmelting 0.3.3 (data-final-fixes.lua)
6.180 Loading mod research-queue 1.5.1 (data-final-fixes.lua)
6.269 Loading mod GDIW 0.15.2 (data-final-fixes.lua)
6.390 Loading mod GDIWHotkey 1.1.0 (data-final-fixes.lua)

This is what I'm using minus the useful combinators as i need to tech up and get them in order to be able to load the game.

Seems there is not anything on that list that should interfere, have you tried reinstalling UsefulCombinators? If it still does not work after reinstalling, I will push out an update.

I've got the exact same error today and after placing combinator from this mod the save loaded without any problems.

Alright, I'm gonna push an update, let me know if it fixes it.