Can you help me to get rid of this error.
Get rid of what 'error'? You haven't posted ANY error or posted the EXACT steps you took to try to do whatever it is you are trying to do.
So start there -explain what it is you wanted to do to begin with:
As the code coverage does not permit to run the procedure on the other schema, i was trying to create UT Schema in another user space as well.
Huh? What 'code coverage' are you talking about? What do you mean by 'run the procedure on the other schema? What 'other schema?
After doing this UT repository is corrupted.
Why do you say that? Don't tell us what you think - SHOW US what you did, step by step, from beginning to end.
I do not understand the problem very well either based on what you have stated so far. From the perspective of the SQL Developer tool development team, it would be interesting to know whether you used only Tools > Unit Test options to arrive at this predicament, or if some processing external to the normal Unit Test feature's workflow took place. If you used only Unit Test, I would recommend logging a Service Request with Oracle Support.
You do not say which SQL Developer release (Unit Test became available in 2.1), but according to the 4.0 documentation (SQL Developer: Unit Testing) multiple unshared repositories can co-exist, but there can be only one shared repository. If the original repository was created, or later selected, as shared (public synonyms get created in that case), then perhaps those public synonyms need to be removed to enable correct functioning of the new repository.
I would try Tools > Unit Test > Deselect As Shared Repository to remove them before taking explicit action to drop any such public synonyms. I assume they would all have the "UT_" prefix. Whatever you decide to try, please give us a detailed description of what happened / happens when posting back here.
SQL Developer Team