You are importing VPM-XML from a remote URL and after installation, the SG tells you that the file was "successfully downloaded and installed". But when you open VPM to verify, you get an error message like or similar to this:
This error message doesn't tell you WHERE exactly the invalid character is and due to the nature of XML, this XML file can be very large.
There is a way to find out in which line the invalid character is: Click on Configuration -> Policy -> Policy Files -> Visual Policy Files -> View the current VPM-XML file:
When you click this button, you will receive an error message that tells you in which line the invalid character is, so you can delete/fix it:
You should be very careful when manually changing the XML, because malformed XML will cause even more errors.