********>Bugfix 18:
Author: Dave Case

Date:   Apr 23, 2009

Programs: sander

Description: Sander's GB code does not allow for extra points; trap this
             combination on input

Use this patch to update amber10/src/sander/mdread.f
------------------------------------------------------------------------------

*** mdread.f	2009-04-23 11:20:23.000000000 -0400
--- mdread.f	2009-04-23 11:21:14.000000000 -0400
***************
*** 1659,1664 ****
--- 1659,1668 ----
        inerr = 1
  #endif
     end if
+    if( igb > 0 .and. numextra > 0) then
+       write(6,'(a)') 'Cannot use igb>0 with extra-point force fields'
+       inerr = 1
+    end if
     if (ips < 0 .or. ips > 3) then
        write(6,'(/2x,a,i3,a)') 'IPS (',ips,') must be 0,1,2, or 3'
        inerr = 1
------------------------------------------------------------------------------
Temporary Workarounds: None