*.gwt.xml module file Here is some into on this note.

If you see this message during your online writing/blogging, this notice is followed by some websites that address this note:

Error: possible problem with your *.gwt.xml module file. The compile time user.agent value (ie9) does not match the runtime user.agent value (ie 10). Expect more errors

Via: Lothar
For a complete discussion:
https://groups.google.com/forum/#!msg/public-data-labs/BQToNk-pxPk/ssi-M9syzV0J
Google public data charts causes an Error in IE9, Windows 7. Message
"Error: Possible problem with you *gwt.xml module file. The compile
time user.agent value (ie6) does not match the
runtime user.agent value (safari). "
In IE7 no graphs are  visible and with IE8 the error occurs only
in .de pages (Windows XP).
Error in  http://www.finanz-links.de/test.htm but not
http://www.finanz-links.com/test.htm though the same code.
Error message in IE8  "Ungültige Klassenzeichenfolge" (invalid class
string)
In  Chrome and Firefox all works fine."