My particules pass trough my plane with right collition settings

I have an emiter, also a plane with collition enabled, damping and friction set to 1 and a -2 strenght setting.

the paricules get atracted to the plane, but they pass through and also the get spited out when they touch the plane why ?

http://www.mediafire.com/imgbnc.php/4a9992d48cad0ca60ee01ee65fb5b92f6g.jpg

here’s the blend file: http://www.mediafire.com/download.php?tywznzzozt5
thanx !

:eek::eek::eek:

solved by tweaking parameters.