I am having trouble using some of my installed bundles, for example, PHP Cake. There are a number of tab triggers I am trying to use, but when I type the sequence and press tab, nothing happens. This behavior seems indicative of TextMate not knowing which bundle to use on the file being edited, though the language association of "HTML (PHP Cake)" in the bottom toolbar is correct.
Not being a user of the PHP Cake bundle, can you verify (via ⌃⇧P) that your caret is in the correct scope for the snippets? If that is the case, then perhaps revert to default bundles[1] and reinstall?
[1]: http://wiki.macromates.com/Troubleshooting/RevertToDefaultBundles