Why Won't A Page Load When Using Mobile Network ?

[eluser]vincej[/eluser]
HI - This belongs to one of those "weird or what" situations. I have built an order processing system using codeigniter ( a very light weight MVC php framework). Amongst many things it generates invoices for orders. It runs faultlessly on a hard wire internet connection.

However, if I run my invoices page over a mobile 3G connection the invoices page fails to display only when there are 5 or more line items on the page. The error message I get back is:

requested content www.mysite/index.php/invoices cannot be processed due to error while parsing reply

However if there are 4 items or less, it runs fine ..... weird or what ??

I have Googled everything and can find only scant references to this error message. Someone suggested that my HTML has to be XHTML .. ok .. I have made certain all my tags are closed I use <br /> however, I do use a few "width" and "valign" ... could that be it ??? I find it unlikely. Also I accept that I have not explicitly created a mobile css - I did not seee the need, as every page renders fine without it, even this one so <i>long as there there are less than 5 invoices</i>.

Does anyone have the vaguest idea what could be going wrong ? Or perhaps where else I can Google ?

I have tried to add my code as an attachment, however I keep getting an error message:

Error Message:
The file could not be written to disk.

Many Many Thanks !