Be Careful About uniqueId Parameter in Stored Procedure

Here is an error I received when my UniqueId parameter in a stored procedure was not valid:

Server Error in '/stockmonger.com' Application.
Conversion failed when converting from a character string to uniqueidentifier.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.Data.SqlClient.SqlException: Conversion failed when converting from a character string to uniqueidentifier.

Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

I corrected to make sure the parameter was a valid uniqueId paramater and not null.