Hi, and welcome :)
Nexus probably meant to welcome you too but probably just forgot ;D
He's right, though. You should be posting code here, in minimal format, so it can be copied directly from the forum. Nobody likes downloading random files. However, I 'risked' it...
You don't seem to have any collision detection at all in your source file so no wonder it doesn't work :P
I noticed this:
sf::Rect<float> p_rect;(pacman_pos,32,32);
sf::Rect<float> w_rect;(wall_pos,32,32);
which, I can imagine, shouldn't have the semi-colon in the centre.
As for simple collision, why not just check to see if the tile that the player wants to move to, is one that allows movement e.g. not a wall.
If you don't know how to work out which tile your player's sprite (or any point) is currently over, this image that I made a while ago for someone else may be of some use:
(http://i.imgur.com/RwmvlfR.jpg)