@Framiga
Yes, you're right :-) But for a moment I was thinking of a helpdesk that I once phoned:
You have an Amiga ?!? Then you can't have DSL.
What!?! 50 Mhz. ?!? -> You can't have DSL

Ok, about the problem... ;-)
Did the provider provide a manual? If so, try to look at the Mac part of it. Most of the times there is a bit more explained instead of a link to an .exe file on a certain CD.
Also if none of this helps, try and find a Linux site that covers this provider. Most of the time on such sites is explained step by step what you have to do.
I haven't got the device you mentioned, so if the prob is related to that... sorry.
Greetz