Prashanti -
>>> Can anybody tell me what is the xml format I need to have my defects in so that it can be used by importxml.pl file?

The bugzilla.dtd (in the same directory as importxml.pl) will show you the correct XML format for use with importxml.pl.

To view a sample of the format, just create a sample bug in Bugzilla, then click "XML" on the line below the "Commit" button.
B-