I think this is a bug but thought I'd post it here first.
When I tried to update the WSDL on Soap UI 2.0.3, the update works fine but when I try to double click on the Binding, so it opens up in the main window, I get an error that a file can not be found.
The xsd files are in a different directory to the WSDL and relatively referenced - that is not the problem. One xsd is relatively referenced from another xsd (in the same folder). Soap UI tried to find that file in the same folder as the WSDL when I double click on the Binding. If I change the relative reference to include the folder name, then it works and the Binding opens up in the main window. However if I try to update the WSDL with the new relative referenced file it breaks (as it should).
Please don't advise me to update to Soap UI 2.5 I did and all my test broke. I am very reluctant to change versions. I just thought I'd mention it in case you had not noticed (if it is a bug) and carried on to the next versions.
this might have been fixed, but we can't be sure until you actually try it out.
Regarding your broken tests with 2.5.x, it might have been caused by the HTTP Version being set to 0.9 when opening the globla preferences dialog, which usually won't work. This is fixed in the latest nightly builds.
If you can share your project/wsdl/etc so we can test this please do so (mail to firstname.lastname@example.org if you like)