Mic and Sound not working right with Mac on Leopard 10.5.6 OSX

I have a PowerMac G5, running Leopard 10.5.6. I am using Paltalk Express. I can't seem to get my mic to transmit to where people can hear me, even though I have the push to talk button and I can see on my settings that the mic is working. I can hear others only if I put my speaker input all to one speaker. If I leave the speaker on equal settings, I get garbled noise in addition to the voice or the voice/noise loops and echos. I've seen several others with a similar problem, but no one has replied with a solution. Thanks for your time and effort in helping resolve this for Mac users!