"3D" is making error!

Hello!
I'd like to know how can I receive some files without mistakes? 
I sent to www4mail@web.bellanet.org :

XBASE=BASE HREF  "http://www.-----.com/stat.htm"
XFORM=<form action "/cgi-bin/webstat.pl" method "POST"> 
user=jhjhjkhkj
password=6766
XSUBMIT_NOW= !!!
XFORM=</form> 
GETSIZE=
GETPART=
XEXTRAOPT=

And File I received -"Invalid username or password"
And some '3D' into:
 
  URL             :  http://www.-----.com/cgi-bin/webstat.pl
?user=3Djhjhjkhkj&password=3D6766
Mail Received   :  Tue May  2 16:10:33 2000
Request Process :  Tue May  2 16:11:22 2000
Delivery Time   :  Tue May  2 16:11:47 2000
User Option(s)  :  getsize=3D getpart=3D

I tried move "getsize" to =10000 or more and "getpart" to =1
Then I received-  "Invalid username or password"

Please write me what to do with the error?