Since some weeks/months I have page rank 0 penalty (white bar) on all
pages of www.xellsoft.com.
search for "Xellsoft","HarvEX","SynchronEX" dont yield my site at all on google.
Months back I had rank 3..6 on many pages.
many pages of the site are linked regularly world wide : popular software
downloads. and DMOZ entries.

even my www.xellsoft.de pages (with completely other content) - a site
which is not linked a lot - has ranks around 4 ! strange.

I have a www.xellsoft.com/links.html with very few stuff in it - but
did not participate in exchange programs. I am going to remove the
links.html.
Will this be a remedy? I think this cannot be the only reason. 
what is the true reason for the penalty? what can I do?