Both GFS 6.0 and GFS 6.1 versions work with 32-bit Linux and 32-bit NetWorker; do NOT work with 64-bit Linux and 32-bit NetWorker
1. GFS 6.0 is supported only by RH AS 3.0.
2. GFS 6.1 is supported only by RH AS 4.0 as detailed below::
- GFS 6.1 on RH as 4.0 x86 ¿ NW 7.2 32-bit version for Linux
- GFS 6.1 on RH as 4.0 x64 ¿ NW 7.2 32-bit version for Linux
- GFS 6.1 on RH as 4.0 x86 ¿ NW 7.3.2 32-bit version for Linux
- GFS 6.1 on RH as 4.0 x64 ¿ NW 7.3.2 64-bit version for Linux
- GFS 6.1 on RH as 4.0 x86 ¿ NW 7.4 32-bit version for Linux
- GFS 6.1 on RH as 4.0 x64 ¿ NW 7.4 64-bit version for Linux

So it seems as the answer is no, but could be that it has not been tested yet for your version.

What is NetWorker license use? (Cluster client connection for Linux or .....).
Can I use normal client connection in this GFS?.

Many Thank.

GFS is clustered file system and as such does not requires cluster client connection as it is not your client that is in cluster.

Many Thanks.
I will testing it on RHEL version 5 again.

Thank.