|Chuck 2, I must agree. The fact that the error is "run dll as an app" is a bit suspicious.|
If you (saurabh 0805) have knowingly been running a 'dll as app' then this is not a reason to panic.
Some software uses this method to run. But if you never had software using this method of running in the past. (run dll as ap)
Then I must agree with Chuck 2, and you need to run antivirus, antispyware software to first confirm and then, clean infections from your system.
Can you give us the name of the 'dll' in question? It would be very helpful. and let us know which antivirus / antispyware software you are using.