Error loading 12.5.2 on Mac data into 12.9.2 on HP

I recently installed Sybase ASE 12.5.2 (Mac OS) on a G5 server. The databases were created in G5 server. A dump taken from an HP server with Sybase ASE 11.9.2 was loaded to the G5 server and tested working fine. Now, I took the dump from the G5 server (ASE 12.5.2) and tried to load it into th HP server (Sybase ASE 11.9.2), and I got the following error:

Backup Server: 6.32.2.1: /disk4/dump/u1.dmp: volume not valid or not 
requested (server: , session id: 106.)
Backup Server: 6.36.2.1: Header labels of rejected volume:
Backup Server: 6.34.2.1:VOL107 HDR1u1043600E771 HDR2F
Backup Server: 1.14.2.2: Unrecoverable I/O or volume error
.  This DUMP or LOAD session must exit.
Backup Server: 6.32.2.3: /disk4/dump/u1.dmp: volume not va
lid or not requested (server: , session id: 106.)
Backup Server: 1.14.2.4: Unrecoverable I/O or volume error
.  This DUMP or LOAD session must exit.

How could I solve this? What is the reason for this error?