[wp-hackers] get_themes(); in WordPress 3.0.5?

[John Eckman]

Background:
Recent releases of wpbook, my plugin in the repo, have been crashing apache
on WordPress 3.0.5 sites. (And perhaps other versions, but notably not 3.1
sites). 

Investigated it a bit, found that a simple call to get_themes(); (at least
in the context of the wpbook plugin) is enough to cause the crash.

Question:

Is this a known issue?

I saw some trac tickets relating to get_themes() but nothing that seemed
obviously related.