CVS failing to label source

I have a build with 11 seperate CVS roots..  2 of these roots are failing to label with the error:

Failed: Failed to set label 'build-3-16-29': cvs rtag: /home/cvs/classpath/ovsSabre.jar,v: no head revision cvs rtag: /home/cvs/classpath/ovsSabre.jar,v: no head revision

For another root:

Failed: Failed to set label 'build-3-16-29': cvs rtag: /home/cvs/dataproviders/sabre/lib/OvsSabre.jar,v: no head revision cvs rtag: /home/cvs/dataproviders/sabre/lib/OvsSabre.jar,v: no head revision

I don't know what the cvs command is that Team City is using to label these roots?

I am simply pulling the HEAD of each root and want to label it with build-x-y-z.

I've tried to cause this issue manaully at the command line with "cvs tag xxxx  "  But it tags successfully.

None of the Team City logs seem to show the actual CVS command that was run that caused this error so I can troubleshoot

Any help?

Thanks,

Gavin