Page For File Upload Stops Processing In Middle Of Log Statement?

We have a very simple ASP.Net page for uploading a file to our webserver. The page has no controls - a client uses it to automatically send us a file each night.

On occasion, the file seems to not get to us, but the client reports that they have sent it.

We added some logging statements to the page, and discovered something quite odd. The page ceases to execute right in the middle of a log statement. No exceptions, just up and dies.

Here is the code-behind:

[code]....

I assume if there was a error in the transmission of the file that either an exception would be thrown from the reader.ReadToEnd() line. And if not an exception, I would expect the page processing to continue but that I may only receive part of the file (in which case it should log something).

The logging statement is only accessing a string variable, and it's inside a try-catch. NLog is the logging component we use, and we access that through the facade provided by the Simple Logging Facade project on Codeplex. So, we trust the logging component to be more or less bulletproof - we certainly don't see anything in our usage of it here that should be causing problems.

Why on earth could this page just up and stop processing like this?

The fact that we get a half-finished logging statement seems to point towards an error being swallowed in the logging system - but that just seems so unlikely - and we have NLog's internal logging on and it is not reporting any problems.