couple of our guys at the shop are having a heated argument and i need to know what page the exact ruling on characters blocking line of fire or how adjacent characters creat walls for line of sight purposes.

thanks

LoF is page 6, terrain is page 11.

BTW, characters never "create walls" for LoF (note, not LoS), even if they obstruct the LoF.

edit: The diagram and language on page 6 should settle your argument. Provided you are using the 2011 (not-yet-printed) rulebook. If you have 2010, or F4, it'll be different page numbers, bear with me here...

2010 rulebook: page 10 for diagram and language.
F4 rulebook: page 9 for diagram and language.

There is a sweet Iphone LOF app out there, It is great for new and old players alike.
It's called ClixUtilities.