iOS 6.0 Quicklook QLPreviewController errors with: "Cannot find preview item for loaded proxy"

Well after a bunch of research and re-creating from the ground-up a basic QuickLook viewer, I found that the error was still logged even from that BUT the documents were actually being displayed which they weren't from my original project.

I then tried putting the QLPreviewController inside a NavigationController before presenting it and ended up with the same issue. I was wrapping the QLPreviewController in a UINavigationController before presenting it because that seemed to be the way to assign the navigationItem a custom button. That worked fine in iOS 5.1 (as stated above) but apparently iOS 6.0 does not like this.

Removing the extra code that wrapped the QLPreviewController in a UINavigationController seemed to allow the document to display.

Example of controller being wrapped:

QLPreviewController* previewer = [[QLPreviewController alloc] init];
previewer.dataSource = self;
previewer.delegate = self;
[previewer setCurrentPreviewItemIndex:0];

UINavigationController* previewNavCtrl = [[UINavigationController alloc] init];
[previewNavCtrl pushViewController:previewer animated:NO];

[self presentModalViewController:previewNavCtrl animated:YES];

Change to:

QLPreviewController* previewer = [[QLPreviewController alloc] init];
previewer.dataSource = self;
previewer.delegate = self;
[previewer setCurrentPreviewItemIndex:0];

[self presentModalViewController:previewer animated:YES];

Note: again the Proxy error still seems to show up in the log however

ALSO: Any UIBarButtonItem customizations seem to no longer work without the NavigationController =/

UPDATE: I found that using fileURLWithpath to generate the fileURL for previewItemAtIndex made the original error go away. However, the same problem occurs still where the document will not load.

A new error (one I've seen other people having as well) is:

Couldn't issue file extension for path: /Users/me/Library/Application%20Support/iPhone%20Simulator/6.0/Applications/339DDF48-AF93-41B5-B81E-A39440A131C6/Documents/temp/Welcome1.docx

FINAL UPDATE: Ok the extension issue/error was because I was trying to manually add %20 to the spaces (using [NSString stringByAddingPercentEscapesUsingEncoding] etc) when the [NSURL fileURLWithPath] must handle that already. Once I removed that, this worked and I am now on iOS 6 yay! So the real problem was nothing to do with the UINavigationController but actually the file URL being passed via previewItemAtIndex.