Not tested but this is first thing that comes to my mind:
Add a propertie in Your form say cikled
In Your code:

scan

Line 1:--code
Line 2:--more code
Line 3:if plcontinue then
          thisform.cikled = .t. 
Line 4:  ThisForm.Bpageframe1.ActivePage = 6 && this is where i accept a password
          DO WHILE thisform.cikled
             DOEVENTS FORCE
          ENDDO
Line 5: endif
>Line 6:--further code here
Line 7:endscan

In the method where You check the password & everithing is OK put
thisform.cikled = .f.

Thiss will work in VFP8 (not in VFP6 because there is no DOEVENTS in it, in VFP7 I am not sure)

Other way is to make a new modal form with password check in it, instead of doing it in Page6:

scan

Line 1:--code
Line 2:--more code
Line 3:if plcontinue then
          DO FORM MyPassWordForm LINKED
Line 5: endif
>Line 6:--further code here
Line 7:endscan

>Hi friends
>
>I have a piece of code which scans thr a cursor and does some processing.
>this code is called from a button on a pageframe's tab.
>sometimes i need switch to accept a password & come back to processing abv code.
>
>my question is how to continue from where i stopped.my sample code
>
>******
>scan
>
>Line 1:--code
>Line 2:--more code
>Line 3:if plcontinue then
>Line 4: ThisForm.Bpageframe1.ActivePage = 6 && this is where i accept a password
>Line 5: endif
>Line 6:--further code here
>Line 7:endscan
>
>once user enters password & clicks ok on page 6 it should continue process abv code
>(from line 5 ofcourse)
>
>Thanks for ur ideas