Running a client gives a DataRequestExecutionResource unknown or not found exception
Then it is likely that a file client-config.wsdd, which the client needs when communicating with an OGSA-dAI web service, is not available in the CLASSPATH.
You should have set your CLASSPATH by running setenv.bat or setenv.sh in $OGSADAI_HOME. And you should have ended up with the directory $OGSADAI_HOME/deploy/ in your CLASSPATH.
If using Eclipse you should configure it to include the directory $OGSADAI_HOME/deploy/ in your CLASSPATH.
Related page in OGSA-DAI 3.1 user doc: