"File Not Writeable" error

[mmtunligit]

Hi, I am having some trouble. whenever I try to download something through the online content browser (including base sounds and effects) or try to save anything I am getting an error message that says "File Not Writable" I've only started having this problem recently, and I've already tried completely wiping my computer of anything openttd related and re-downloading the game. I assume I'm missing a directory for some reason. I'm currently running the jgrpp-0.31.1 pack and I had to manually install opengfx. Any help is appreciated, thanks!
EDIT: I might have found the problem, the whole folder is read-only, but any time i try to uncheck the box, it just reverts to a read-only state after i close the properties window

[Eddi]

try to delete your openttd.cfg, so the game can recreate it (and the download folder) in a place that is writable