It seems to be related to apc memory pool having trouble to allocate memory:
[Tue Jul 30 06:55:27 2013] [error] [client 31.35.45.30] PHP Fatal error: Allowed memory size of 205520896 bytes exhausted (tried to allocate 657010689 bytes) in /usr/share/codendi/src/common/frs/FRSFile.class.php on line 497, referer:
https://tuleap.net/file/showfiles.php?group_id=101
The sad part is that it might be a sign that we have trouble downloading big files in php53