Beaver, how long did you allow the Bud keg to acclimate to your kegerator? Also, what are your specs on the system? Get back to us.
Fuberman, yes you do need to maintain temperature every inch of the system. Unless you want a beer chilled system, install a blower. Stella is a relatively stable import and should be fine based on your settings. 20 year old regulator? Although most of the parts are metal and hold up well if in a friendly environment, the diaphragm is not metal and normally rots over time.
Topgun, give me your exact specs and brands. Let's get to the bottom of this before you resort to the aluminum can[:0].
Scott Zuhse, Instructor
Micro Matic Dispense Institute