In web.config file, there is an innappropriate character on line 9:
<add segment="store" />-
Interesting. The source file does not contain that character, but the 3.0.8 release does. This is possibly build script related.
I noticed that with my editor, if I do a copy/paste of the line, the character is not copied.
I think the problem is the file charset (UTF-8 with no BOM).
Try changing the file charset with your editor, and see the result.
The character is definitely there in the source file in develop-olympus: https://raw.github.com/phpbb/phpbb3/develop-olympus/phpBB/web.config
It appears as if it's always been there:
Interesting that I never noticed this before.