Vim and ack-grep: quickfix not opening files -

i'm @ loss.

i'm running debian lenny, vim 7.3, , i've tried both ack-grep 1.80 , 1.96. added line .vimrc:

let g:ackprg="ack-grep -h --nocolor --nogroup" 

[when include --column error not valid option, that's why tried upgrading ack-grep.]

when execute :ack, quickfix window shows matches in form:

|| folder/subfolder//file.rhtml:30:def do_it 

i can use :cn, :cp, etc. methods. cannot vim open files. both return , o nothing.

what missing?!

try emptying vim (all plugins , settings) except ones necessary ack-vim. help?