Both of these plugins require that Vim be compiled with Ruby support, you must compile them using the same version of Ruby, etc. Is there a plugin that performs the same task but does not require installation other than removing it to a directory vimfiles?
UPDATE: these plugins allow you to open files / buffers by typing characters that appear in their path, and not necessarily in a string. That is, if there are files in your directory
foo/bar.txt
foo/baz.vim
zee.c
you can enter
,t f
and only two matching files are displayed; after adding r, only one file remains, and it can be opened by clicking <Return>.