You seem to be in a confused state. Don't worry.
You just installed NOM on a 32 bit server. Thats fine.
Having 64bit clients should not be a problem. It does not cause issue with the NOM server with it being 32bit.
Suggest you do some reading in the NOM dept.
Veritas NetBackup (tm) 6.5 Operations Manager Guide
http://support.veritas.com/docs/290227
VERITAS NetBackup (tm) 6.0 Operations Manager Getting Started Guide
http://support.veritas.com/docs/279292
294409: DOCUMENTATION: Additional information on using the Windows NetBackup 6.0 client with NetBackup Operations Manager (NOM) 6.5.
http://support.veritas.com/docs/294409
279064: DOCUMENTATION: No information appears in the Veritas NetBackup (tm) Operations Manager (NOM) Console after the initial installation.
http://support.veritas.com/docs/279064
283614: DOCUMENTATION: How to install the Veritas NetBackup (tm) Operations Manager and supporting software on Windows systems
http://support.veritas.com/docs/283614
284162: DOCUMENTATION: Known installation problems associated with Veritas NetBackup (tm) Operations Manager when VxSS is installed as "root-only"
http://support.veritas.com/docs/284162
284178: DOCUMENTATION: Known installation problems associated with Veritas NetBackup (tm) Operations Manager (NOM) when NetBIOS or Client for Microsoft Networks is disabled.
http://support.veritas.com/docs/284178
284277: DOCUMENTATION: Unable to run the NOM console if the root broker has been installed on a different system
http://support.veritas.com/docs/284277
285150: Veritas NetBackup (tm) Operations Manager (NOM) 6.0 Maintenance Pack 4 (MP4) Getting Started Guide Revision 1 for Windows and Solaris (last updated November 2006)
http://support.veritas.com/docs/285150
286072: GENERAL ERROR: Errors occur when attempting to upgrade the NetBackup Operations Manager when it is installed on the same system acting as a NetBackup master server
http://support.veritas.com/docs/286072