index.html IE problem -free web template 7

index.html won't open menu pages in IE (6 and 7).
It works ok in firefox.
First page is index.html, all others are .htm

OS is win xp sp2. I use Tempate7. I tried it on different computers.
In IE works only index.htm
My site is not yet on web, it's still under construction.

This is the error message for i.e. _kontakt.htm page:

"Cannot find "file://D:\Documents and Settings\Maria\My Documents\My Web\index.htm?page=_kontakt.htm'. Make sure the path or Internet address is correct."

Here i see IE try to open index.htm not index.html, but i don't know what to do to change this.

On all computers are both browsers and on all is firefox default.

Please help. Thank you

p.s.
the same problem is for default.htm and default.html
(on my home comp, the others comps are now not available)

p.p.s
the same is with template 8 and template 9. any idea?

p.p.p.s. problem is in function myButton. how to fix it?