Hello,
Could you let us know what version of SEP are you carrying??
Do you have a different Domain created in the SEPM?
To check the same: Login to SEPM as "admin", then go to Admin TAB> Domains
Could you let us know how many domains do you see?
If there are 2 domains, then to which is the Limited Administrator created for?
Accordingly, make sure on the SEPM Login screen > Click on Options Button and then insert the Domain Name (same as the Domain name within the SEPM)
Check this Article:
After configuring limited administrators within the SEPM, the users are unable to log in
http://www.symantec.com/docs/TECH143769
Hope that helps!!