First of all this question has been asked at least twice.
I tried several approaches with no effect.
Here's the problem:
When I try to download/update plugins like EclEmma, Eclipse starts to communicate with the repository and that takes about 5 minutes. After that I get an error:
"An error occured while collecting items to be installed session context was:(...)
Unable to read repository at http: (...) Read time out
(... for every *.jar)"
What I was trying to fix the problem was running eclipse as an admin (got vista x86 running) and changing the connection properties from native to direct and back. I also tried deleting saved repositories and adding again. No effect at all.
I have no proxy configured and don't need one.
This is getting kind of personal between me and my IDE :D
So I hope you guys can help me out.
Thanks Zoltán (köszi :D), but i found the error last night.
Resolution
After hours of debugging I figured out that AVG Anti-Virus Software blocks the request. After deactivating it for temporarily, Eclipse installed the new software.