I ran into an issue where the following lines were being repeated in my console log 10 times every 5 seconds:

11/30/07 12:23:21 PM com.apple.SystemStarter48 Break on __THE_PROCESS_HAS_FORKED_AND_YOU_CANNOT_USE_THIS_COREFOUNDATION_FUNCTIONALITY___YOU_MUST_EXEC__() to debug.
11/30/07 12:23:21 PM com.apple.SystemStarter48 The process has forked and you cannot use this CoreFoundation functionality safely. You MUST exec().

After gnashing my teeth about this for several weeks, I finally ran across a reference that said NUDC might be responsible. I removed the NUDC folder in /Library/StartupItems, restarted, and the problem went away.

I just installed beta 3 of 5.3.2 and the problem appears to be fixed in that version. I'm running 10.5.1.