Restore dmp file :error during backup/restore: unable to open device

Dear,

I received from a developer a dump database file (db.dmp) from sybase version
12.5.

My environment is Sybase Central Version 16.

I tried without success on my server to restore the dump file.

We get this error message : "error during backup/restore: unable to open device"

Thanks if anybody could help me to figure out this issue with success.

Best Regards,

Youssef