Unable to write license usage info to ND

I have a mixed NW 5/5.1 WAN environment. The tree is divide up into three partitions ROOT,SA_OB,WEST_OB. On three of the NW 5.1
servers, I’m getting the following errors:

2-05-2001 2:25:45 pm: SERVER-5.0-0
NLSLSP.NLM: Warning:Unable to write license usage information to NDS. Historical usage information may be incomplete. Check “O=WEST” partition synchronization. Service will continue. OB_WEST.WEST_OB.

I get this error on three of the NW 5.1
servers,AD_SALK,AD_SANDBURG,and AD_EAST. AD_EAST and AD_SANDBURG are in the ROOT partition and got this error twice within an hour. I ran NDS Manager against the WEST_OB partition and do not come up with any errors. Any ideas? Let me know. Thanks.