...from an alias and when I replied it said:

"There was a problem!
User: _____________ Not Found."

So I tried typing in the alias in the 'To' box and got the same message.

I copied and pasted the alias also and that didn't work either.

i never PM any aliases..why bother..i have no time to communicate with any one who obviously does not want to be communicated with..

that I was in Classic TER, and supposedly if I use the new version, I can then respond to the alias PM.

I haven't tested out that yet, however.

Which version did you try to respond in?

All 3 methods you tried should work if you are in "new." Doesn't work in "classic."
If you were in new and those methods didn't work, then it's either a glitch or the alias no longer exists. (he sent you a PM then changed his alias?

...mentioned it before but I forgot.  Thanks guys!

by the way, how do I get the new version?

Are you sure you are actually able to PM an alias on classic? Because BigPapa and mrf and bostonguy and others all have had problems, and I tried it myself (even though I normally use the new TER) and it didn't work.

We will give up our Classic TER when you peel our steely cold death grips from it.