Did you ever have an INTERNAL workspace access before? I think we cannot have access to INTERNAL workspace as ADMIN user in apex.oracle.com, You should download Oracle Apex install and use it on your own to get admin privilege for INTERNAL workspace.
apex.oracle.com provides users a workspace of their own to try out the product(APEX) and try developing applications, not giving access to their INTERNAL workspace as ADMIN
Your application resides in your workspace not INTERNAL workspace of apex.oracle.com. Any problems with your application should be addressed by login into your workspace. Hope this helps
Are you insatll any packaged application in your workspace?
then click over name of application and unlock it.
for this reason ferer Oracle Database Development Tools (ODDT): APEX 4.2.3 enhances sample and packaged apps
Contact the admin for APEX hosted instance accounts.. from the help link at font page of Oracle's Hosted APEX instance:
This hosted Oracle Application Express instance is provided as a free demonstration service to anyone. Use of this system to store sensitive, offensive, unauthorized, or illegal data is prohibited. You are also prohibited from running production applications on this service.
The purpose of this e-mail account is for Administration requests only. Any questions related to functionality or issues of Application Express should be posted on the Oracle Application Express OTN Forum.
This e-mail account is checked periodically throughout the business day. But please do not expect an immediate reply or resolution.
found solution to unlock application
this will help you when you need Rollback of 'Application Build Status' for your application which you have changed into 'Run Application only ' ,
Go to Home->Administration->ManageService->Application Build Status (Right side link)
and change status of application to run and build application