parameter dependency error

Hi,
My ssrs report has several datasets.
One of them uses a stored procedure (sp) which takes two parameters.
When I try to run the report, the error is:
The report parameter 'MyCode' has a defaultvalue or a validvalue that depends on the report parameter 'TableName'

The parameter 'TableName' is refering to the dataset as mentioned above which uses sp

Any thoughts please?
Thanks