Narahari,
Can you open the same file with other editors, such as the MyEclipse JSP Editor or the Text Editor? Does it happen for all of your JSF based JSP files?
I can’t replicate it here but the stack trace might indicate something odd about your project or file. Is the file physically in the workspace? It might be worth trying a fresh workspace and importing your project into it, then trying again.
Let me know if any of these suggestions work.