WEBDEV XI & AJAX

when i select one row in one table (JAX ENABLE) i need to refrsh one HTML control.
I always get one error in IE the detail is PAGE_A17 (alias of the html control) is null or without content.

I'm doing like this:
AJAXExecuteAsynchronous(server_proc,brw_proc)

PROCEDURE SERVER_PROC ()
...
// HTML1 is one HTML control in the page
RESULT HTML1

PROCEDURE BRW_PROC(par1,par2)
HTML1=par1

What is my mistake?
PS:
The content of HTML1 is OK, i tested in another page whith one HTML control and the same content and everything works.

My control HTML1 was one HTML CONTROL.
I delete the control and create it as HTML STATIC CONTROL and it works.