I created a house and i wanted to add an animation to the packaged lot. So I unpacked all files from the packaged lot as .package; moved them to a folder and added the animation.package.
The I tried to create a new .sims2pack as described in the manual
(http://sims2pack.modthesims2.com/index.php?page=4#7).
But when I want to press save (Step 6) this error occurs:

I reinstalled S2PCI with cleaning the registry, I reinstalled Framework + sp1. But nothing helped .

Did you clear the preview image checkbox? I've never had much luck getting this program to make fresh Sims2Packs- you could always zip the animation up in a file with the Sims2Pack if you are sharing it, or give a link if you are uploading it.

yeah i unchecked the box for the preview image

I suggest you follow simsample`s suggestion of placing it in the archive, but outside the Sims2Pack file. As a downloader, I prefer that my downloads incude stuff NOT in Sims2Packs whenever possible.