[AccessD] Access form and report anomalies

I have found two confusing problems with a database I am writing.

1. I have a tab form where the record source is decided from a combo box. 
The record sources are both queries that are changed depending which tab is 
picked. both queries rely on a record number in a hidden field. If I leave 
the data in this field as is when changing record sources the form works 
perfectly except that the data on the chosen tab form uses the record 
number from the other form to display its data. I tried to clear the data 
in this field so that each time a form opens it opens clean. but I kept 
getting the message that I was changing the record  source and the form 
would crash. This only happened to the second of the form tabs while the 
first still kept working fine. Does anyone have any ideas what may be 
causing this.

2. I have four similar reports that for some reason print in triplicate 
everytime they are run. This results whenever these reports are run, even 
if they are just previewed. Other than this hiccup the reports work 
perfectly. I hope someone can help me out of my confusion and to solve this 
anomaly.

TIA

David