Just released a fix, turns out I had already fixed it in March and even made a .zip ready for upload, but never actually uploaded it.
The issue was caused by me changing the name of the toolbelt technology to toolbelt-1, so that the names would not be weird, but that breaks everyone else's technologies that have toolbelt as a prerequisite. The solution is to iterate through all of the technologies during the updates phase (after almost all mods should have added theirs) and, if they have toolbelt as one of their prerequisites, change it to toolbelt-1.
This of course will use more time the more techs you have, but it shouldn't matter that much as the time taken should grow pretty much linearly with the number of techs, it only runs at startup, and it really isn't doing that much (just iterating through global tables and comparing strings).
