problem in gmax making maps

[dracolord]

in all of my maps i get errors with open edges when i try to make the scenario file in tool

it has open edges in 4 spots every time
heres the message :

building intermediate geometry...
building collision geometry...
### ERROR edge #15 is open (red).
### ERROR edge #37 is open (red).
### ERROR edge #39 is open (red).
### ERROR edge #471 is open (red).
### ERROR failed to build collision geometry.
### ERROR failed to import collision bsp.

these edges form a triangle shapes

i have tryed making edges where the open ones are, but it just causes more errors.
if need be i can provide the files
http://rapidshare.de/files/34210879/a__ ... .gmax.html
http://rapidshare.de/files/34211111/rock_orig_.wrl.html

thanks for any help you may be able to provide

[a mammoth]

select everything around it and weld the vertices at a thing of zero or very close zero. That may solve the problem. Sometimes extra verts get sneek in there.