This particular session (
http://www.be-at.tv/brands/dc10/para...13/jamie-jones) have
0000.beat file which contains different AVC sequence header than rest of other beat files. it seems they restarted video encoding with different parameters after first few seconds. this causes problems with most players because they expect only one decoder configuration packet per stream. you can leave out
0000.beat and try to join the rest. it should work properly though i have tested it only on first few fragments.
for the 2 GB problem it's a limitation of php which uses signed 32 bit file pointers limiting the file size to 2 GB. if you are using a 64 bit operating system (greater than xp) you can download
64 bit php and try with that.