Reasons for Unexpected end of file while parsing Name has occurred

[Anna Wójcik]

Hi,
I have read some threads about this error and also encountered it few
times. Till today I thought it has something to do with diacritical
letters in data secondary sources but today I did this modification to
my infopath 2007 form that is published to site content type:
-Added one field to main source - not promoted
-Added one view
-Added "Save" button.
-Added one opening rule to be able to see new view regarding to new
field value
The form is web enabled.
Now, when I click "Save" on new form it saves properly to document
library. But when I click "Save" on every other next view I get "There
has been error while processing a form" > "The form has been closed".
And error in sharepoint log:

Forms Server Forms Services Runtime 8gec
Exception Unhandled exception when rendering form
System.Xml.XmlException: Unexpected end of file while parsing Name has
occurred. Line 1, position 525. at
System.Xml.XmlTextReaderImpl.Throw(Exception e) at
System.Xml.XmlTextReaderImpl.Throw(String res, String arg) at
System.Xml.XmlTextReaderImpl.Throw(Int32 pos, String res, String arg)
at System.Xml.XmlTextReaderImpl.ParseQName(Boolean isQName, Int32
startOffset, Int32& colonPos) at
System.Xml.XmlTextReaderImpl.ThrowTagMismatch(NodeData startTag) at
System.Xml.XmlTextReaderImpl.ParseEndElement() at
System.Xml.XmlTextReaderImpl.ParseElementContent() at
System.Xml.XmlTextReaderImpl.Read() at
System.Xml.XmlLoader.LoadNode(Boolean skipOverWhitespace) at
System.Xml.XmlLoader.LoadDocSequence(XmlDocument parentDoc) ...

Anybody know how to diagnoze what is really going on while form
processing, what is root of the problem? Any help really really appreciated.
Regards,
Ann W