I'm unable to reproduce your issue.
I've also checked if it e.g. only fails when the cookie is imported from Firefox (as I usually use Chrome) but that's working fine too.
Here is what you can try to re-check my assumption that only the "phpssid" cookie matters:
1. Use Chrome for this test.
2. Install the free- and open source Chrome addon EditThisCookie: editthiscookie.com
3. Visit soundsnap.com, stay in this tab, click on the EditThisCookie symbol and delete all soundsnap cookies except "PHPSESSID".
4. Now refresh the soundsnap tab --> Check if you are still logged in.
If so, your current PHPSESSID cookie should also work fine in JD.
-psp-
|