I have written a DLL in Delphi 1.2 that reads values over the serial port and then displays them in different graphical formats. I also have an MDI C program (written by someone else) that calls my DLL. USUALLY when there are several MDI Child windows open & some simple disk access has been performed, and then my DLL is called I get an EResNotFound exception. It is trappable, and on the second call to my DLL everything works just fine. The exception occurs during the line: MainForm := TMainForm.Create(Application); Also it ONLY occurs under Windows 3.11, with Windows 95 it works ok. It is not a memory availability problem as there is more than enough around.I am already aware of the StrToFloat problem in Delphi 1 DLL's and I have compensated for it.The problem has an uninitialised memory/wrong segment feel to it, but I can't seem to find out why or where.I would be grateful if anybody can throw any light on the problem at all.