tile collision detection help needed...

i have made a reasonable attempt at my own collision detection routine for a tile game. However i have run into a snag. I created a tile that reduces the player's speed by half, however it does not work as i intended it. it slows the player down perfect, however it makes the player jump back and forth when he is on a slowdown tile and against the wall. this makes it near impossible to move through a narrow gap with the slowdown tile there.

It sounds wierd i know, but if you could download my sourcecode and compile it you will understand better!

if anyone could tell me what i am doing wrong, or why i am getting this jumping effect and some idea to get rid of it, i would greatly appreciatte it. And i do check every single tile each time the player moves. But i will fix that later.

Thanks for your time!

Werdy666:rolleyes: