DO NOT use long file/path names when you´re typing the .PAC file name on (#!$@%*$) IE7, use good old plain 8.3 file names ! ( Many thanks to Billy Gates of Hell for all the time I´ve lost figuring this out - the boy doesn´t have a clue on how many bad karma he´s generating for himself )
If you´re not an old command-line dinossaur like me you may have trouble figuring the pretty little things out. Don´t worry !
Just enter a command prompt ( execute cmd.exe ), go to the root of the driver where your .PAC thing is ( type C:[ENTER] and CD\[ENTER] ) and use DIR /O to see the short names.
You´ll see something like PROGRA~1 for the "Program Files" folder, for example. Enter the folder you need ( CD <short-name-of-the-folder>[ENTER] ) and repeat that for every folder level ( don´t forget to annotate the whole stuff ).
For the last folder level DIR may fail to show the short name( way to go again Billy ). Do not curse Micro**** more than absolutely necessary, the rule Paindows use for making this names is "Take the first six characters - ignoring spaces - and put the tilda and a number ( depending on how many folder long-names begins with the same six characters ). Some exceptions may occur: the tilda may not be present ( the default is to be there, but this is a registry configured thing - some registry tweaking programs can let you change that, althought I´ve never seem to be able to figure out why somebody would wanna waste a single milisecond messing with this stupid setting ) and if you have diacriticals on your folders names ( like me, because I speak Portuguese ) things can get a little fuzzy: sometimes they´re just ignored, sometimes they got replaced for ASC II characters you don´t have on your keyboard ( go figure ).