When iTunes uses the interval time function to update Squeezecenter database, it misses up the entire database for SC.

It seems like it picks the new music but it replace the entire database with new scan instead of adding the new files it finds to the existence database.

The workaround is to set the interval time to zero, but in that case no new music added to iTunes will be scanned, unless that is done manually. 

SqueezeCenter Version: 7.2 - 22900 
Mac OS X 10.5.4 (9E17) - EN - utf8
Perl Version: 5.8.8 darwin-thread-multi-2level
MySQL Version: 5.0.22-standard

Some of errors
[08-09-09 07:47:16.4948] main::main (220) Error: Skipping post-process & Not updating lastRescanTime!
[08-09-09 08:28:10.2071] main::main (219) Error: Failed when running main scan: [Can't call method "content_type" on an undefined value at /Library/PreferencePanes/SqueezeCenter.prefPane/Contents/server/Slim/Schema.pm line 1155.

(RN- 080909-003688)