This error usually occurs when authorizing Concept, Proworx or Control Expert 14 (Unity Pro software. The SKCL.dll must reside in the \windows\system32 or \winnt\system32 folder. If it currently resides in this folder, you may need to register the .DLL.
To do this, bring up a DOS shell and type:

c:\> regsvr32 skcl.dll



You should then be able to launch the Authorization utility.