I get this too with all flavours of 4.0 - 64 bit jdk7, 32 bit jdk 1.6 and Eclipse plugin running under jdk 7. But, since the jdk 7 issue is described here:
http://www.soapui.org/forum/viewtopic.php?f=13&t=8188&p=23658&hilit=nullpointerexception&sid=2860e2819387961261236c384442fe98&sid=2860e2819387961261236c384442fe98#p23658, I will stick to jdk 1.6 issues.
These errors occur trying to open the tutorial wsdl so its not the wsdl (also occurs with my wsdl):
First, I get the dialog in the attached png.
Then, i get to choose the wsdl file, but the console text attached is produced. This results in a window where the project is displayed with the soapUIStarterPage displaying with an error.
Cheers,
TheCaptn