WinEraseRectangle and PalmOS 3.5

[Mick Doe]

Hello!

I have a part of source code which works fine for all Palm OS except 3.5
(palmos35-dr4-en-colordbg.rom). Here it is:

// Draw "please wait" form
 FormPtr frmWait = FrmInitForm (WaitForm);
 FrmDrawForm(frmWait);
// Do something lengthly ..
 FrmEraseForm(frmWait);
 FrmDeleteForm(frmWait);
//
....
 FormPtr frm = FrmGetActiveForm();
 FrmHideObject(frm, FrmGetObjectIndex(frm, Field1)); // error is here
 FldSetTextHandle(ctx, (Handle) HandleText);
 FrmShowObject(frm, FrmGetObjectIndex(frm, Field1));

The error is two strange letters (I use CW5, POSE 3.0a3 W98) .. the
stack is:
    ...
    FrmHideObject
    FldEraseField
    WinEraseRectangle - movea.l  26(a3),a2 - error at this instruction

What does it mean? How can I avoid this?

Any help is welcome!

Regards,
Mick Doe