Ok, so at this point, I'm at a loss. I've gone through the Haloscan code insertion instructions at least a dozen times but still can't get the comments to work. I've dumped my existing blog template code, and re-tried the Haloscan installation to no avail. I've read the Haloscan forum and tried a couple of "unofficial" methods found there, but still no luck.
The strange thing is that even without the Haloscan comment-code, the default Blogger comments should work, but they don't.
If anybody has any bright ideas, email me at gmr 2048 at yahoo dot com.