It may be then that the "memory alloc" message is simply to alert the operator that more than one call to the -exec utility was needed. I.e., it manages to process everything... but just alerts the operator that it wasn't all done within a single call.
Nope, it means exactly what it says: fts_read ran out of memory when trying to read a directory. My guess is that you've either got a
really big directory somewhere on the disk, or that the disk is nearly full and there isn't much VM space.
