line-in recording problem

I just recently purchased a V-Amp 2 hoping to hookup the output to my soundcard line-in. At first I tried to use my SBLive 5.1 Dolby Digital card but I didn't get any sound from the V-Amp 2. My motherboard (Biostar M7NCD Pro) has the nForce2 6.1 onboard sound so I tried hooking it up as well (making sure to disable the other card). Still no dice. I even tried to tap the input to the V-Amp to see if it was giving any feedback...nope. I then tried to us my Ampeg combo amp to send a line out into the line-in on the soundcard. 0 for 3. Now, here's where it gets weird. I have a small practice amp I use to take anywhere. I can plug my guitar into this amp, run a speaker line out to my soundcard and I can hear sound on the pc. WTF??? Then I ran my V-amp through the practice amp and then to my soundcard. While I can hear sound, it's not all that loud and starts to degrade with even a little gain. This has really been pissing me off because I know the soundcard should be able to handle the sound out of the V-amp alone or even from my Ampeg. Does anyone have any ideas I could try? I'm pretty stumped here. Thanks in advance.