I'm starting up a new world (and thus new mods) for a 1.7.10 world with some friends, and I have gotten every other mod we would like to be installed and stable, but Project:Red seems to cause a crash upon loading. At this point, MrTJP core being installed works, but when I add the base mod, there's a crash. I've tried a couple different versions, and always get the crash.

The crash report is here:
https://www.dropbox.com/s/qzwyz4qps6v1rwi/Crash%20Report.txt?dl=0

That version of ProjectRed is incompatible with that version of MrTJPCore
Either update ProjectRed to 4.5.10.61 or downgrade MrTJPCore to 1.0.3.5

That was the problem. I must have tried every combination except the one that works. Thanks, closing this.