Browser displays blank page, while request still being handled

Hello everybody I'm having some strange behaviour in a PHP4 app I'm working on. When I send my request to the server, it returns a blank page to me within ca. 40 sec. On the server itself, my request is still being handled. The script behind the request does the following: - delete some files - copy files from dir A to dir B - read some data from a database and generates some XML-files (i.e. a basic "publish" procedure) The problem isn't the script itself, nor the server. I know this, because the same code is being used on the same server for other instances of this application. The only difference between the problem-app and the other apps is that the problem app has: A) a lot more files needing to be copied (number of files and size) B) a lot more (stale) records in the DB Another strange thing is, that when I try to view the source code of the blank page, my browser asks me if I want to send the request again :-( I've been searching the Web for a long time now, and I'm really desperate for some answers. If anyone could help me, even a hint of where to start, it would be greatly appreciated. With kind regards and many, many thanks in advance Rolf Wouters