Download works locally but not on remote server.

I've developed a page on a church website to listen to and download mp3 files as well as read and download text and pdf files.

On my testing server on my PC (Vista) (WAMPSERVER2) it all works brilliantly, even though I say so myself. I can play the mp3 files, see the pdf and txt files in the browser (by clicking on the linked text) and by clicking the download button the files are offered for download by the browser (FF3 and IE8).

I have now uploaded all the files to the server and it's gone a bit pear shaped.

I've made sure that all the dependant files are uploaded as well.

The mp3's play fine.

By opening the TXT and PDF files in the browser window (clicking on the linked text) the files open fine to be read in the browser.

The download buttons however just open up another browser window and in the case of PDF and MP3 display "rubbish" and in the case of the txt file it displays unformatted text. It should offer the files for download.

I've used DigitalFilePro2 for this.

As it works locally but not in the remote browser I've asked the hosting people in case it's just a setting in the php.ini file, or some other setting.

Can it be something to do with DFP2 or is it more likely the web server? If so, any ideas what?

Here's the page again