Hi Prsekaran,
Your original issue of not starting Navisworks could be tied to a corrupt Cascadeinfo.cas file.
http://usa.autodesk.com/adsk/servlet/ps/dl/item?siteID=123112&id=14340444&linkID=10382101
A reformat of your system corrected the original error, but I expect the above link may have been your cause.
As for your exception issue- depending on where the exception occurs, errors of this nature can be tied to graphics card conflicts (An exception while opening or navigating a model) or installation corruption (An exception while starting the application).
First, turn off your Hardware acceleration. This can be done with Navisworks closed.
1.) Click
Start > Programs > Autodesk > Autodesk Navisworks **YOUR VERSION** > Options Editor and the
Options Editor window will open.
2.) Click
Interface > Display and uncheck “Hardware Acceleration”.
3.) Click “OK” to close the dialog.
4.) Try to start Navisworks.
Next I would update your Graphics card drivers to the manufacturer’s latest available version. Specific CAD drivers do not necessarily work best for Navisworks.
If newer drivers do not prevent the exception from occurring, I would “Repair” your installation from the Control Panel and retest. If the error occurs after a repair, uninstall the application entirely and delete the following folders on your system:
C:\Autodesk\Navisworks Simulate 2010
C:\Documents and Settings\**YOUR USERID**\Application Data\Autodesk Navisworks Simulate 2010\
C:\Program Files\Autodesk\Navisworks Simulate 2010
Turn off your Antivirus and any other unnecessary desktop widgets and install Navisworks.
Thank you for participating in our community!
David Dembkoski, Autodesk Product Support
Edited by: dembkod on May 26, 2010 8:58 PM
David Dembkoski