This could be caused by the known bug that the driver installer sometimes does not copy atiadlxx.dll and atiadlxy.dll to sysWOW64.
Check them if they are missing. If they are there also check the filedate, because they might be from an older version.
Copy atiadlxy.dll from the C:\AMD\... folder to SysWOW64 and rename it to atiadlxx.dll and also copy it again with the original name (atiadlxy.dll).