the scenarion is like this...
I HAVE a namespace XXX where I created some tables and some stored procedures...
THEY HAVE a namespace YYY<
In your stored procedures on schema XXX if you access tables from YYY schema, make sure you fully qualify them:
select count(1) from YYY.TableA;
Other thing to consider is casing (in case you are mixing upper and lowercase in your Oracle identifiers).
One last thing: post the error you are getting. It will be easier to help you that way.