You should not install to any "Program Files" directory, with or without the "x86" suffix because RTW assumes certain things which are no longer true in/since Windows Vista. Incidentally the x86 suffix seems to denote 'for programs designed for the x86 architecture', or slightly less correct 'for 32bit programs'.

Your error message (missing oliphaunt models, I take it?) seems to indicate a corrupt version of the text file which manages mount models (descr_mounts ?). Or a mismatch between that one and the DMB... IIRC it has been caused once by a bad/corrupted download in the past, but that would be the 0.8 days...