dmadmin.exe is a logical disk manager admin. Every time you add or change a drives partitions this process is run. If it is running you shouldn't end it because it will end itself.
Fix dmadmin.exe Errors: Free Scan
Spanish Windows 2000 logical disk manager administrative service
Logical Disk Manager Administrative Service
Veritas logical disk manager
Every attempt has been made to ensure the information about dmadmin.exe is accurate but alot of malware applications try to pose as valid applications. If it is something other than what was posted above please leave some feedback in the forum.