Missing required argument to Append command

Got the same problem in ubuntu 11.04 i386

I have a similar problem (on 11.04, KDE updated through the backport PPA). It also devoured my emails. When I turned on the spam/anti-virus filters, it deleted them from the IMAP server (my email provider is GMX), ran the checks, then tried to upload them back to the server and I got a similar message; "could not upload the message ..." "unexpected end of data." The net result was that the email was deleted, and was not present either on my computer or the server. I lost a few days of emails, until I found a work-around (firstly using thunderbird to read email, then switching off the spam/anti-virus filters on kmail).

dpkg -l | grep kdepim
ii kdepim 4:4.4.10-0ubuntu4 Personal Information Management apps from the official KDE release
ii kdepim-groupware 4:4.4.10-0ubuntu4 KDE PIM Groupware plugins
ii kdepim-kresources 4:4.4.10-0ubuntu4 KDE PIM resource plugins
ii kdepim-runtime 4:4.4.10-0ubuntu2 Runtime components for akonadi-kde
ii kdepim-strigi-plugins 4:4.4.10-0ubuntu4 PIM file format plugins for Strigi Desktop Search
ii kdepim-wizards 4:4.4.10-0ubuntu4 KDE server configuration wizards
ii kdepimlibs-kio-plugins 4:4.7.0-0ubuntu1~natty1~ppa1 kio slaves used by KDE PIM applications
ii libkdepim4 4:4.4.10-0ubuntu4 KDE PIM library

Affects me too under Kubuntu 11.04 64bit

Getting the "unexpected end of data." thingie, too ... 11.04, amd64

The error occurs on messages that are moved to subdirs by filtering when the arrive ...

https://bugs.kde.org/show_bug.cgi?id=279432

The remote bug is about an older version. (Is the information really correct in that bug?). This bug IS about kdepim 4.7

Same problem here; using a local IMAP server messages seem to disappear on filtering with the "Error while uploading message" notification. Same with GMail IMAP, although fortunately in GMail they don't disappear but only get removed from the inbox; still show in All Mail

I disabled the automatic spam filtering and messages stay in the inbox.

Running KDE 4.7.0 with KMail 1.13.6 on Kubuntu 11.04.

To clarify, this is *not* about KDEPIM 4.7 - the fact that the original report has KMail 4.4.10 proves that. I can confirm that I've also experienced this issue when upgrading to KDE 4.7 via the backports PPA, which does not contain the new KDEPIM; one can only assume that one of the libraries it uses has some kind of bug or incompatibility with the older KDEPIM that is the root cause of this issue.