If the SAS 9.3 catalog was created on the same operating system (i.e. Linux) as the SAS 9.4 you need to read it with, then it will work.
However, if the SAS 9.3 catalog was created on a Unix system (AIX, Solaris, HP-UX, ...) and you need to read it with SAS 9.4 on Linux, this will not work. It needs to be read with SAS on the same Unix system as it was created on, exported, and then imported in to SAS 9.4 on Linux.
Hope this helps.