Can't read Cadworx 2008 files

Caesar build(5.10) of Feb.7,2008 requires .C2 files from Cadworx.
Cadworx 2008 Nov.5,2007 build only outputs ._a files.
Is there a patch we are missing?
Thank you

In the "File Open" dialog box, at the bottom you'll find a drop list. Change the file type from "*.C 2" to "*._ A".

There was no choice of file extensions. But I did find the problem.
Inthe config file the Caesar version was set to 4.5. Once set to 5.00 or 5.10 it works fine.
Thanks
Allan