Problem in User Decision Step

Hi,

I am facing a strange problem where one of the User when he is trying to process a work item (User Decision) he gets a blank screen.

This work item is a User Decision Step. Only this user is facing the problem. At least the button Cancel and keep Work item

In Inbox button is also not visible.

He was earlier able to see the other buttons. Is it any authorization problem? Has anyone faced a similar kind of Issue.

I tried executing the Txn SWIA to execute the work item and see the problem .But I don’t see the execute button to execute it as an administrator.

Do I need additional authorizations to be able to execute it? If so what are they? I am able to see the execute button in my QA sys.