(The phone number is extremely hard to find at their website, and many of the businesses they "operate as", because they have a digit missing from ther phone number in the InterNIC database.)
[Update: 2009-01-26 ... the InterNIC listing for digitalriver.com has been updated to have the above phone numbers, perhaps updated on 2009-01-26!]

A reader writes:

   After a long search I found the Digital River phone number on your site,
   thank you. They now have a second number for their Element5 branch which =
   is 952-646-5022.

Digital River owns (or operates as) a number of online software registration companies, including swreg.org.
(InterNIC last updated 2008-07-23, with missing digit in phone number.)

The swreg.org web page / software rejected all my attempts with "illegal country" (even though "United States" was selected from the drop-down list). The first time I reported it, they ignored the report completely. (Well, as far as I can tell they ignored it ... the attempt may have triggered some PayPal-hater at Digital River to jump up and down in glee, who knows?! :)

The second time I tried to buy dBpoweramp through swreg.org (2008-03-09), selecting PayPal, I got the same error ... and reported it again. This time I got a response [now lost] ... one so bad it led me to wonder if the support person was able to read English. I replied, and got back:

   The the issue may be with PayPal.  

   SWREG is a payment processor as is PayPal.
   
   We process the credit cards.
   
   You may want to contact the vendor through their website to see if there is 
   an issue with PayPal.

   We apologize we cannot assist you.

   Kevin

Yeah, right ... the instant error on the swreg.org page of "illegal country" is from another vendor? That's bullshit. Now, I don't know: is Kevin really that stupid, or is he evil (e.g., instructed to close support calls with that canned response if he doesn't know how to solve them?).

I gave in, and bought the software via a credit card (instead of PayPal, which I prefer).

Swreg.org emailed me a download link, and said I had 7 days to download the product.

I tried a download ... and aborted it after 4KB because I was getting 100 **BYTES** a second. Tried again. and again. Waited a few minutes, tried again. Rebooted (hey, you never know! :) and tried again. and again. Waited four hours and tried again. Oops...I'm being rejected, "too many downloads". The incompetent that wrote their code didn't realize: you're supposed to increment the download counter only after a successful download.

I submitted a support request (via the web ... they don't allow email, of course):

   Re: the order # below.

   I tried about a dozen times to download it today ... I'd get about 100 *BYTES*
   per second, not kB ... so I abandoned each attempt.
   
   Now, you won't let me try at all!
   
   You owe me ... besides the time wasted trying to download from your system,
   there's the cost of the software (dBpoweramp Reference).
   
   I want a working link, or (if you prefer) email me the software
   to my alternate (GUI) email: ss@allegrosupport.com.

   thanks,

The asinine, arrogant, lying reply:

   Written by SWREG:Customer Support at 172.20.20.234 on 10 Mar 2008 14:17:18

   Dear Vendor,
   
   Please contact the customer as they are requesting a refund for this order. 
   The customer is not satisfied with the product and the customer has notified 
   SWREG regarding this issue. Do you authorize the refund? Please assist the 
   customer with this issues and cc us on your response.
   
   Thank you
   SWREG
   
   Kevin

(I contacted dBpoweramp to let them know that I'm happy with their product, and do not want a refund ... they make a great CD ripper!)

The moral: avoid Digital River, in all its incarnations.