I've just updated K2 to 2.5 and Joomla to 1.5.25. Prior to this I was working fine with Image Gallery zip file loads. Now everytime I try to load a zip file to the Image Gallery of an Item I get
"UNKNOWNARCHIVETYPE. Gallery upload error. Cannot extract archive."

I'm using Simple Image Gallery Pro.

I can upload and extract the zip file using Control Panel / File Manager. I can load the images using Filezilla. But neither of these methods actually results in an image gallery on the item, because the gallery field in the K2 item table is not updated with the {gallery}item id{/gallery}.

If I load the images using Filezilla and update the gallery field in the K2 item table manually then I get my image gallery but obviously this is not ideal.

Any soluton / ideas or do I have to revert back to 2.4 and / or 1.5.23 (last working versions)

Actually i found the fix

/administrator/components/com_k2/lib/class.upload.php

After in the same file change (line 2231)
$this->file_src_mime = mime_content_type($this->file_src_pathname);
...to...
$this->file_src_mime = mime_content_type($this->file_src_name);

Hello

Joomla Joomla! 1.5.24 Stable, K2 K2 v2.4.1, sig pro 2.0.5

We're having same problem with sig pro 2.0.5, getting an error

UNKNOWNARCHIVETYPE Gallery upload error: Cannot extract archive

after my host provider moved our page to new srv:

Apache/2.2.21 (Unix) mod_ssl/2.2.21 OpenSSL/1.0.0-fips mod_auth_passthrough/2.1 mod_bwlimited/1.4 FrontPage/5.0.2.2635 , PHP 5.2.17

All this was working on previous srv without problem.

All of the known solutions provided (in arhive forum) didn't worked,

Provider won't upg PHP to 5.3.8, whitch is the only solution we didn't try! Any other ideas left???