Msg 6602, Level 16, State 2, Procedure sp_xml_preparedocument, Line 1

Msg 6602, Level 16, State 2, Procedure sp_xml_preparedocument, Line 1
The error description is 'Whitespace is not allowed at this location.'.
Msg 8179, Level 16, State 5, Procedure XXXXX, Line 45
Could not find prepared statement with handle 15.
sp_xml_removedocument: The value supplied for parameter number 1 is invalid.

Whe you parsing xml document, xml tag string contain invalide character li ",&,use

http://forums.microsoft.com/msdn/ShowPost.aspx?PostID=3576805&SiteID=1

XmlReaderSettings readerSetttings = new XmlReaderSettings();
readerSetttings.CheckCharacters = false;

best decribe
http://forums.microsoft.com/MSDN/ShowPost.aspx?PostID=1723005&SiteID=1