Error while running event what-items-do-i-have::on_lua_shortcut (ID 42)
what-items-do-i-have/control.lua:344: attempt to call global 'get_player' (a nil value)
stack traceback:
what-items-do-i-have/control.lua:344: in function <what-items-do-i-have/control.lua:340>

I can also add:

15122.771 Error MainLoop.cpp:1468: Exception at tick 3515146: The mod P.U.M.P. (2.1.15) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event pump::on_gui_click (ID 1)
The mod What Items Do I Have? (1.2.13) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event what-items-do-i-have::on_runtime_mod_setting_changed (ID 69)
Invalid ItemID: expected LuaItemPrototype, LuaItemStack, LuaItem or string.
stack traceback:
    [C]: in function 'get_item_count'
    __what-items-do-i-have__/control.lua:257: in function 'search'
    __what-items-do-i-have__/control.lua:322: in function <__what-items-do-i-have__/control.lua:320>
stack traceback:
    [C]: in function '__newindex'
    __pump__/toolshop.lua:339: in function 'close_tool_picker_ui'
    __pump__/control.lua:25: in function <__pump__/control.lua:21>

Those are two different errors. Please report them separately

Fixed in latest release