So really this is a flash question. Your problem is “scope”. If this doesn’t work either repost here or do a search on the flash forums for “scope”.
I have tried your tutorial on my local computer. However it did not work out. I suspect the problem is with ASP file. I have checked the ASP codes you provided hundred times. No way. I tried this on my local computer in IE. http://localhost/processform.asp and it shows me an error message. However I used another simple ASP file (writing “Hello World!”) onto the screen and it works. In sumary, help me!