soapui test cases fail after installing loadui

i just installed loadui. i tried running web service test cases in soap ui and all of the fail and give this error:

line -1: error: The document is not a Envelope@http://schemas.xmlsoap.org/soap/envelope/: document element mismatch got definitions@http://schemas.xmlsoap.org/wsdl/
line 1: The document is not a Envelope@http://schemas.xmlsoap.org/soap/envelope/: document element mismatch got definitions@http://schemas.xmlsoap.org/wsdl/

the tests ran successfully before installing loadui. what is causing this error?