C# - Could Not Find File "C:WINDOWSTEMPxxxx.dll

I know this question has been asked many times and I have done some extensive research on the internet to try and resolve the issue but everything I have tried has failed and I really need to sort this issue out, hence my post. Here is what I have tried:

Change the directory in which the temp files are stored. (Changed locally to each website). Store the XMLSerialization object in a global variable and use that instead of creating a new one each time. Delete all temp files in the windows temp folder. Set permissions on the windows emp folder (I have them set to everyone at the moment just to try and resolve the issue).

My Setup is as follows:

IIS7 on windows 2008 dedicated server.

The website is written in ASP.NET using Delphi.

I have several XML files that need serializing so not just one.

My website talks to the web service and processes the XML (I am guessing this is the part that is breaking everything)

Here is an example:

This is the code for one of my XML files. StockXMLSer is held globally and after testing is only created once per site.

function IntGetSTOCK_ITEMS(S: TStream): STOCK_ITEMS;
begin
if not Assigned(StockXMLSer) then begin
StockXMLSer := XmlSerializer.Create(STOCK_ITEMS.ClassInfo);
OutputDebugString('StockXMLSer Serializer Created');.......