OK, got 6.1.71223 installed on Windows XP at home.
To reproduce problem:

Start estudio.  Click Cancel.
Undock Standard buttons toolbar and move quickly up and down over tool bar area (docking and
   undocking) until estudio crashes (usually within 10 seconds).
Click on Submit Bug.
Enter username "aaaaaa" and password "aaaaaa".  Click Submit.
When estudio reports error 23, click OK.
Click on Submit Bug again.
Enter username "aaaaaa" and password "aaaaaa".  Click Submit.
Estudio reports uncaught exception with trace (seems to be a slightly different
trace than the one I got previously):

-------------------------------------------------------------------------------
Class / Object      Routine                Nature of exception           Effect
-------------------------------------------------------------------------------
STRING_8            infix "+" @1                                        
<0000000005953770>                         Feature call on void target.  Fail
-------------------------------------------------------------------------------
STRING_8            infix "+" @1                                        
<0000000005953770>                         Routine failure.              Fail
-------------------------------------------------------------------------------
EB_EXCEPTION_SUBMIT_DIALOG
                    prepare_data @11       
<0000000005904B38>                         Routine failure.              Fail
-------------------------------------------------------------------------------
EB_EXCEPTION_SUBMIT_DIALOG
                    on_submit @6           
<0000000005904B38>                         Routine failure.              Fail
-----------------------------------------------------------------------------