When I installed it, by default the new sides were off. When I turned them back on, whenever I joined a game, I crashed.

Check the directory of the sides and see if they are in the right place, or, just use a backup of the sides and use the stock soldiers.

EDIT: Does this happen in singleplayer or multiplayer?

I probably should have mentioned this when I gave you the link (my bad, sorry), but r129 ditched the visual changes, saying if you wanted them, you could download RepSharpshooter's 1.2 patch, which was what the side changes were for the 1.3 patch...

I'm going to assume the crash was caused by you running r129, then trying to reactivate the side changes from r117. A simple reinstall of r129 should fix the crash, then install Rep's Unofficial 1.2 patch to get your sides.

Nope. Uninstalled the r117, then installed 129. But since it didn't work I went back to the 117.

r129 is supposed to wipe out any files from all earlier versions, so it shouldn't be possible to reactivate the side changes from r117. If menu.bat still existed, it's a bug (and/or file permission issue) that it wasn't deleted.

There is no option in r129 that has the word 'side' in it, so I don't know what you many by "I turned them back on". Can you explain in a little more detail? There is a Use the v1.2 HUD option...