Multi-page Archives Link Incorrectly

I’m having issues with the archives at:

http://www.davecopeland.com/index.php/blog

When a user clicks an archive link at the right, they are brought to the first page of archives for the given month (this part works perfectly). However, when the user reaches the bottom of the page and clicks on “Previous entries”, they are returned to the 2nd page of the main blog, instead of the 2nd page of the desired archive.

The Previous Entries link is:

http://www.davecopeland.com/index.php/page/2/

…when it should be:

http://www.davecopeland.com/index.php/2006/02/page/2

I imagine this an issue with the next_post_link() tag, but I don’t have enough WordPress experience to know for sure.

Any input would be GREATLY appreciated. Thank you.