If the exactly the same application works on other app servers, and the pages should ultimately be loaded from ClassPathStores (which they almost certainly are) then it's almost certainly a classpath configuration problem with WebLogic. Unfortunately I don't know anything about configuring WebLogic nor very much about WQS (although I know about Spring Surf) but I'm guessing you might need to explicitly configure the Classpath access for the application (?)
You shouldn't need to re-configure the Spring application context that defines the Surf object stores that are used to look up the pages if they are working on other app servers. It doesn't look like the default WQS application overrides any of the Spring Surf defaults. The object stores/persister configuration is quite complex and scattered across several Spring application context configuration files in the Spring Surf and Spring WebScripts JAR files… they in the "org.springframework.extensions.webscripts." and "org.springframework.extensions.surf." packages. There is also an "autowire" service which updates some of the persistence/object store configuration… however, as I said - if it's working on other app servers you really shouldn't need to touch any of that. However, it might be useful as reference for working out how configure your applications Classpath in WebLogic.
Hope this helps, apologies if it's a bit vague but the best I can do without deep WebLogic or WQS knowledge,
Regards,
Dave