Sometimes when Im experimentating with Hammer and want to compile my map, it says
"Entity weapon_portalgun (256.00 256.00 1.00) leaked!".
always in compination with a "couldnt read..." Error.
Its not always "weapon_portal gun". Sometimes its "prop_button" or something else...

Does anyone know whats the problem?
thx

I came across a problem similar to this and it was because I was moving my player start location and the location of the portal gun around (for testing). On one of the moves, I put them partially in a wall and they "leaked" out of the map.

If that doesn't fix it, maybe this will help...

http://developer.valvesoftware.com/wiki/Leak

thx it works now

vbsp.exe produces a "pointfile" when the map is leaking. Load the point file (Map -> Load Pointfile) and you'll see a red line from the entity that leaked.