Index: openacs-4/packages/acs-developer-support/www/index.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/acs-developer-support/www/index.tcl,v
diff -u -r1.18 -r1.19
--- openacs-4/packages/acs-developer-support/www/index.tcl	9 Jan 2010 01:56:09 -0000	1.18
+++ openacs-4/packages/acs-developer-support/www/index.tcl	18 Nov 2012 17:17:08 -0000	1.19
@@ -11,7 +11,8 @@
 ds_require_permission [ad_conn package_id] "admin"
 
 set enabled_p [nsv_get ds_properties enabled_p]
-set user_switching_enabled_p [nsv_get ds_properties user_switching_enabled_p]
+set user_switching_enabled_p [expr {[nsv_exists ds_properties user_switching_enabled_p] ? 
+				    [nsv_get ds_properties user_switching_enabled_p] : 0}]
 set database_enabled_p [nsv_get ds_properties database_enabled_p]
 set profiling_enabled_p [nsv_get ds_properties profiling_enabled_p]
 set adp_reveal_enabled_p [nsv_get ds_properties adp_reveal_enabled_p]