Proflem opeening PDF from modaldialog in IE76.0

I am facing problem in IE6.x.x. when opening pdf document for modaldialog. Some security warning appears and the PDF not getting open. Can you suggest how to solve this problem. This happens only in some machine. We checked all the browser settings in the PC.Any suggesstions please?

Getting : Security Warning instead of opening PDF. In the warning pop up i can see the file name : my URL
File type : Un known file type

If i click "open", or "save" or Cancel the window is getting closed.

I checked the browser setting also. Everything is fine.

Please note : This happens only in some machine, not every time. Who affected this problem only first time from next time there is no issues. All documents are getting opened successfully.

Please post me if any body facing this problem and let me know the solutions if any.

Thanks in advance.

<moved thread - was off topic for Slow Chat >