Depending on the bundle item the exact error for a failing Textmate2 bundle can change, but his is the one I was getting for "Comment Line / Selection" on a previously pristine Textmate2
Comment Line / Selection:16:in 'require': no such file to load -- /lib/escape (LoadError)
from Comment Line / Selection:16
How do I fix my bundles?
First try this:
Delete this file: ~/Library/Caches/com.macromates.TextMate/BundlesIndex.plist
Then relaunch TextMate.
This is a problem with the cache not properly updating when bundles
are changed on disk (as they would have been recently, as a lot of
bundles got updated) — so far though I only know it happens, not why it happens…'
Source: Textmate Email List
Then, if that doesn't work, try this:
Textmate -> Preferences -> Bundles and uninstall and reinstall "Bundle Support"
then quit and relaunch Textmate.