Clamwin finding Email.E-card-* but not removing

Clamwin is finding Email.E-card-* (where * is a number between 1 and 8 so far) and reporting it in its virus scan but isnt removing. No other program seems to find it and the only mention I can find on the web is in a log that someone posted that never got responded to.

The actual entry looks like this;

C:\Documents and Settings\Andrew\Application Data\Thunderbird\Profiles\milzkgw4.default\Mail\Local Folders\Inbox.sbd\ACCOUNTS: Email.E-card-5 FOUND
C:\Documents and Settings\Andrew\Application Data\Thunderbird\Profiles\milzkgw4.default\Mail\Local Folders\Inbox.sbd\ACCOUNTS: Not deleting/moving mailbox
C:\Documents and Settings\Andrew\Application Data\Thunderbird\Profiles\milzkgw4.default\Mail\Local Folders\Trash: Email.E-card-7 FOUND
C:\Documents and Settings\Andrew\Application Data\Thunderbird\Profiles\milzkgw4.default\Mail\Local Folders\Trash: Not deleting/moving mailbox

What do I do?

I have run AVG, a-squared, Avira, HiJack this, CWShredder and all of them report no infection.

Is this a false positive that should be ignored?