Help! When adding watermark product images disapear?

[VirtueMarky]

Hi,

i want to add watermarks to virtuemart category and detail images.

I followed this instructions but i have some problems.

http://mtkcode.blogspot.de/2013/07/apply-watermark-image-into-product.html

I did it exactly like this but once i put the .htaccess in the folder "images/stories/product/" the images of the category and detail dont show up anymore.
In the source i can see the correct url to the image. If i copy this url and paste it behind the domain it redirects me to the mainpage.

Is there something i can do about this? Sounds so easy in the instructions?

Thanks