Multiple SubForms - SQL Statement

I'm new to programing so if this is not possible please tell me! Because this is going to be hard to explain I attached an example.

I have a Main form that a user will open, this is the only window that will ever pop up in front of them so it has a subform that will open differnt froms by picking buttons on the left.

One of the sub forms is the Member Information form, this form will show member information than at the bottom has another subform that will allow a user to pick a button above it to open another subform (this is so member info is always show and a member can be registered, pay...all different subforms)

on the Event Register subform the "Class" pulldown is based on the event that was pick just above it.

Issue:
when I am in the main form, I can not get the class pulldown to work it always prompts me for "enter Parameter Value". I have tried the following SQL statements in the row source and noting work.. what am I missing???


SELECT SubCatList.SubCatName, SubCatList.EventName
FROM SubCatList
WHERE (((SubCatList.EventName)=[Forms].[MainFRM]![MemberInfoFRM].Form]![EventRegFRM].[Form]![EventName]));

and

SELECT SubCatList.SubCatName, SubCatList.EventName
FROM SubCatList
WHERE (((SubCatList.EventName)=[Forms]![MainFRM]![MainSubFRM]![Form]![memberinfoFRM]![MemberSubFRM].[Form].[EventName]));