Delphi's SOAP implementation does appear to not like the XD feature on the newer range of Intel microprocessors. SOAP calls will in some cases simply fail with a few Access Violations. Very useful information to know, if you happen to own a new machine... In this case the classic developer excuse ("But it worked on my machine!") might actually be true!

Edit (16/02/2006):

A quick fix is to switch off XD in the BIOS. Otherwise, if you happen to run Windows XP or have a PC without such a BIOS setting, you can edit the DEP (Data Execution Prevention) settings under the Advanced -> Performance Settings tab in the system properties. (Simply add your program to the list to disable DEP.)

Note that this also happens on newer AMD cpu's with DEP technology.