could be a rev19 issue. This is from the error code index on the site:
Wad Install Error Most likely have cIOS 37 (or other outdated/incorrect IOS) still installed. Memory might be full. Wad may be corrupt (patched/injected incorrectly).
Q. How do I fix this Error?
A. Fix it by uninstalling IOS249 (use AnyTitleDeleter) if you have it installed. Try using Custom Wad Manager, as some cIOS may be incompatible with the normal Wad Manager. Try a different wad.