WyE5JZhXEX: Do you mean the Destination folder when you run widescreen-v2.60.exe ? Did you install Planescape to the default which is C:\Program Files\GOG.com\Planescape Torment ? If so, browsing to there when you run the widescreen mod installer should work.

However, I understand that Windows Vista and Windows 7 have security clamps on Program Files - I don't know the details as I'm still on Windows XP, but I think it prevents writing there by untrusted programs. If that's the problem, the safest solution might be to uninstall Planescape and create a games folder elsewhere, say C:\Games and install it there. Then install the widescreen mod to C:\Games\GOG.com\Planescape Torment or whatever path you chose.

There are other solutions to the permissions issue, but it depends on your level of knowledge.

Am I on the right track or am I barking up the completely wrong tree?

WyE5JZhXEX: You need to click Browse for the destination folder and navigate to wherever you installed the game, but maybe I'm not putting this well, so I'll list the steps and you can tell me where you are stuck.

1) Click on widescreen-v2.60.exe
2) In the Widescreen Mod window, the Destination folder is filled in for Baldurs Gate 2 default path, so you need to Click on Browse to search for the Planescape Torment path, which by default is C:\Program Files\GOG.com\Planescape Torment which should appear as you open up the My Computer and C folders etc.
3) Click Install.

I'm wondering now if you were confused by the Baldurs Gate path C:\Program Files\Black Isle\BGII - SoA which is pre-typed for you in the Destination folder and needs to be changed for Planescape Torment?