Cascading prompt with custom values.

[CognosTalk]

Greetings,
I am experiencing the error when running report.
I created a custom values for the parameters, which gets displayed in the first paratemer.
I set it to auto submit.
Then based on the value chosen on the parameter 1 parameter 2 gets populated.

After choosing parameter 1 and auto submit the error is:
QE-DEF-0359 The query contains a reference to at least one object '[Union1].[Parameter Group Type]that does not exist.


I am not sure why. this object exists in a separate query and it displayed values on the parameter1
i am able to execute each query that i have for the report.

Any comments will be highly appreciated.

The value that i am calling in parameter2 is

CASE
WHEN ?ParameterGroupType? IN ('Reg 170') THEN [Drinking Water].[Parameters].[O. Reg. 170 Parameter Group]
WHEN ?ParameterGroupType? IN ('CDWI') THEN [Drinking Water].[Parameters].[CDWI Parameter Group]
END


?ParameterGroupType? - is my fists parameter.