After several lab test server 2003 installs with the same Adaptive Agent login errors we finally found a solution. We eliminated the possibility of certificate or dns errors pretty quickly.

Login Error;
Unable to log into the network because the login credentials or the server certificate is incorrect

One of the forum posts HERE, pointed us in the direction of a CASA service problem.
We downloaded the ZCM 11 Diag files from Novell patchlink and after running it found that almost all the files under the "C:\Program Files\Novell\ZENworks\share\tomcat\webapps\CasaAut hTokenSvc" folder were missing.
We eventually found that the WAR file was located at "C:\Program Files\Novell\ZENworks\share\ats\catalinabase\webap ps" that contains the CasaAuthTokenSvc files, we stopped the CASA server service, Zenworks server and Zenworks Loader services and extracted the CasaAuthTokenSvc.war file contents directly over the top of "C:\Program Files\Novell\ZENworks\share\tomcat\webapps\CasaAut hTokenSvc".
After rebooting the server everything was working perfect, doing this did fix the problem.

We then wanted to find out why the ZCM install log did not tell us why the CASA files didn't install correctly and what initially caused the error.
After plenty of testing and vm workstation snapshots and reverts we found that if the Windows 2003 Internet Explorer Enhanced Security feature was uninstalled before installing Zenworks that the CASA files would install correctly and everything would run fine.

The following link details the Enhanced IE security Config Internet Explorer Enhanced Security Configuration changes the browsing experience

While I wouldn't recommend disabling this feature it seemed to cause the problem for us, re-extracting the CasaAuthTokenSvc.war file and rebooting would be the recommended way to fix it until Novell solve the problem.

One thing to note as well if this is the problem, the CASA logging feature doesn't work until you extract the CasaAuthTokenSvc.war file and reboot either, we could not get CASA server service logging to work until the file was extracted and server rebooted.

I would like to know if this solves the problem for other people, please post back.

Hope this helps someone else or at least saves some time with this problem.