MythTV trouble

I've been playing with KnoppMythRD50 on a machine with the following specs:

Asus A7N266-C motherboard
AMD Athlon XP 1600+ (1.4GHz) CPU
256MB DDR PC2100 (I have 512MB of PC2700 coming)
250GB PATA hard drive
Hauppage PVR 150 with IR-Blaster
ATI X1300 256MB AGP video card
10/100 NIC
Viewsonic 19" widescreen LCD

I signed up with Zap2it, and KnoppMyth appears to have correctly found all my channels. The problem I'm finding is that playing or recording media doesn't seem to work. I tried playing a show and just got a black screen on my LCD. Is it possible to display out to monitor/LCD or do you have to configure Component/S-Video out?

Recorded shows also don't seem to be recording. There is a small .nvu (or similar extension) file, but no mpeg or avi. I checked and both transcode and mpeg appear to be installed.

*** UPDATE - Problem Solved ***
The solution was simple. KnoppMyth by default selects V4L for the capture card (while displaying that the card is a Hauppage PVR 150). I just changed this to a MPEG2 encoder and was able to capture shows. 256MB isn't enough memory. Any other use of the machine seems to corrupt video while it's recording. The 512MB should help. I've read people experiencing no problems with 256MB RAM, but I'm a bit skeptical.