Using the same Private3-SSH-1.ppk file in both programs?
Yes, that one or the original.
I'm at a loss in that case. There can be other reasons a public key wouldn't work with a given server, but they should result in different error messages (or the same key not working via other clients).
Exactly.
I'm back on this. I'm not supposed to be sending my public key here, but my private one apparently. The server has my public key.