why? :
???
It’s like hell for dial-up connection users 
: ???
that’s what I mean :-\
Good point. I remember, when it was just first days I use internet, and my first experience of it was dial-up. I’ve used avast with my computer since times when it hadn’t any internet connection (it was 300MHz celeron 
) During my first avast program update dial-up connection was lost, and I had to wait another half an hour to update the program. :-\ it was long time ago (maybe 2 years ago) but I know, how dial-up users feels…
Have you tried downloading from download.com , majorgeeks.com or betanews.com their servers supprt resume ?
I use FlashGet and it does support resuming from the official server of avast :
Are you sure the problem isn’t in the download manager application?
Yeah i can confirm that… Download Express sometimes says there isn’t any resume support when is and vice versa…
So, why worry, just test if the resume can be achieved after all ;D
Problem is that Download Express will stay at that and won’t even try to resume it…
Another good reason to start using StarDownloader. Best of all, it’s freeware…
http://www.snapfiles.com/freeware/downloader/fwdown.html
Scroll down a bit…
Strange thing, using Maxthon, Star Downloader doesn’t launch just hangs so it looks like the IE integration doesn’t crossover to Maxthon, even though I have Star Downloader as the default download manager in Maxthon.
Also star downloader integration extension no longer works with firefox 1.5 rc2. The default downloader for firefox works and that would also appear to support resume if you pause it but not if you lose the dial-up connection.
All avast servers ofcourse support reget. The problem must lie somewhere else.
I’ve partially downloaded the same file as you, stopped it in half and then I made ‘wget’ downloader to continue downloading. See the debug output below. It clearly sends the partial file.
Sorry that this does not help you, but at least it shows the problem is not in the server settings, so you may investigate somewhere else.
F:\>wget -c -d http://download17.avast.com/iavs4pro/setupeng.exe
DEBUG output created by Wget 1.5.0 on Windows.
parseurl ("http://download17.avast.com/iavs4pro/setupeng.exe") -> host download17.avast.com -> opath
iavs4pro/setupeng.exe -> dir iavs4pro -> file setupeng.exe -> ndir iavs4pro
--12:07:30-- http://download17.avast.com:80/iavs4pro/setupeng.exe
=> `setupeng.exe'
Connecting to download17.avast.com:80... Created fd 1944.
connected!
---request begin---
GET /iavs4pro/setupeng.exe HTTP/1.0
User-Agent: Wget/1.5.0
Host: download17.avast.com:80
Accept: */*
Range: bytes=9964-
---request end---
HTTP request sent, fetching headers... HTTP/1.1 206 Partial Content
Date: Wed, 16 Nov 2005 11:07:33 GMT
Server: Apache
Last-Modified: Sat, 12 Nov 2005 16:17:46 GMT
ETag: "32d787-977500-94113e80"
Accept-Ranges: bytes
Content-Length: 9915924
Content-Range: bytes 9964-9925887/9925888
Connection: close
Content-Type: application/octet-stream
done.
Length: 9,925,888 (9,915,924 to go) [application/octet-stream]
so FDM has the same problem :
Mina, FlashGet resume easily form avast servers…
Problem is on the application and/or browser.
Did you try Download Acelerator Plus?
Tech, AFAIK DAP has a spyware in it :
Oh… I’m surprised… I have this software into consideration, but, if you’re right… no more…
I also have FlashGet. After just testing, I can confirm that FlashGet detects the Alwil servers as being able to resume on an interrupted download… (it works fine on my end! 
I have just tested a free download manager called Netleech (www.netleech.com) and it works fine also.