I have a system set up to download jad files on users' Blackberries, but it only works intermittently, and seemingly randomly. If the user clicks on the link within their BlackBerry browser, 95% of the time on the first try an error message will pop up saying there was an HTTP 500 error (which our server never returns).

Viewing the details of this message within the blackberry browser, it says nothing but java.lang.nullpointerexception which, again, could not have come from our server (running apache/php).

However, if the user clicks on the link a few more times, or navigates away and goes back to that page, it suddenly works. No change on the server, it just shows the application install screen. Unfortunately, this doesn't always work; sometimes the error 500 just keeps showing up.

The link is rather long (containing an sha hash as a token as part of the URL), but I would think that a long URL would either always be broken or always work, not work intermittently.

The link uses a php script to download the jad and cod files. Linking to the files directly rather than using the script seems to work more often (I haven't determined if that also ever has an error 500 or not), but I can't find any issues with the headers. The content type is set correctly and, like I said, if the headers were an issue, I'd think it would either always work or always break.

Any clues?