*** Moderator Note: I've moved your question over to the Oracle Application Express product space as it's clearly a question about APEX and is NOT feedback about the OTN community. The clue was in the name of the space you posted... "Community Feedback (No Product Questions)" - please take care to choose the correct product space in future.
You haven't given any detail about your environment, so I'm making assumptions here that you're using Oracle XE and that you've possibly upgraded the version of APEX that's shipped with Oracle XE, and are still expecting to be able to access app 4950. Is that correct? If so, then you'll find a number of associated posts on this topic, such as Error App 4950, after upgrading 11XE (Windows) from the Apex 4.0 to 4.2.4 and an associated OTN page: Upgrading Oracle Application Express in Oracle Database Express Edition.