Hi all, chiming in.
The issue is due to a validation error. From what I understood, the plug-in uses DTKit framework and a set of XSD's (and maybe other validation schemas) to validate the input files.
In the case of the nosetests.xml file, I used the plug-in version from GitHub, branch master. Debugging the plug-in looks like it uses junit-7.xsd  from DTKit.
If you are curious, copy the contents of nosetests.xml attached to this issue, and the junit-7.xsd contents, and paste them at http://www.utilities-online.info/xsdvalidation
The following error message is displayed:
Error - Line 1, 110: org.xml.sax.SAXParseException; lineNumber: 1; columnNumber: 110; cvc-complex-type.3.2.2: Attribute 'skip' is not allowed to appear in element 'testsuite'.
I'll take a look at the DTKit to see if it's possible to send a pull request to its repository.