I get an error whenever I startup, it starts loading the mods I got (all for B19/20) and then about halfway through a bigass ERROR- blahblahblah abort screen blah blah base.rte entry = null or something like that.
There doesn't seem to be anything wrong with base.rte, considering it is in its entirety there.
Edit:
Abortion in file .\system\contentfile.cpp, line 647, because:
Failed to load datafile object within following path and name:
base.rte/devices/null.
The last frame has been dumped to 'abortscreen.bmp'

Look in Base.rte for a file called Null.bmp.

Make a copy of that file and put it in Base.rte/Devices.

Problem solved.