Here is an interesting article from the Solidworks Knowledgebase which can address some issues when using eDrawings to view files.
What can cause eDrawings to launch but fail loading the file with “Unsupported file type” error when using View option (in button bar, history, notification) in Enterprise PDM?
Go to the administrator application.
Expand vault and right click on the ‘Users’ icon and choose Settings.
Click on the ‘Viewers’ tab and click on the Installed Viewers for sldasm, sldprt, etc.
On the bottom there is a ‘Path and arguments to viewer program;’ the path should be something like this
C:\Program Files\Common Files\eDrawings2009\EModelViewer.exe”%1%”
Make sure there is no SPACE before or trailing after the “%1%” argument. Also the error will manifest itself if there is no path filled in at all.
Note that on a x64 system eDrawings is installed under C:\Program Files (x86)\….”