Well, I'm up, but my eyes aren't as functional as they were a few hours ago. ;)

There's only one thing I can immediately spot - that you're declaring the parameters in your SP as nChar, yet you're not specifying the parameter type of nChar when the parameter objects are being created.

Again, I don't know much about nChar. But in the absence of specific requirements for Unicode, you should change your two parameters in your stored proc to char(10).

If you truly need unicode, then my guess is that you'll have to change your parameter types in your .NET piece to be SqlDBType.NChar.

(Earlier I did a test where I had nChar as the SP parameters, yet passed the parameters as text, and got an error - so you might be encoutering the same thing)

Kevin