ActiveX controls not enabled in Access97

I am trying to add the Calendar control to an
Access 97 form on my NT 4.0 workstation.
When I try to use the insert ActiveX Control,
nothing is listed. When I attempted to
register the control from the Tool/ActiveX
menu, it allowed me to select the mscal.ocx
program, but did not actually register the
file.

Is there an incompatibility between Windows
NT and ActiveX controls in Access, and if so,
is there a way to correct the problem?