Index: openacs-4/packages/xotcl-core/tcl/install-check-procs.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/xotcl-core/tcl/install-check-procs.tcl,v
diff -u -r1.6 -r1.6.2.1
--- openacs-4/packages/xotcl-core/tcl/install-check-procs.tcl	7 Aug 2017 23:48:30 -0000	1.6
+++ openacs-4/packages/xotcl-core/tcl/install-check-procs.tcl	23 Jul 2019 17:06:23 -0000	1.6.2.1
@@ -7,7 +7,7 @@
     @author Gustaf Neumann (neumann@wu-wien.ac.at)
   } {
     ns_log notice "-- before-install callback"
-    if {[info commands ::xotcl::Class] eq ""} {
+    if {![nsf::is object ::xotcl::Class]} {
       error " XOTcl does not appear to be installed on your system!\n\
      Please follow the install instructions on http://www.openacs.org/xowiki/xotcl-core"
     } elseif {$::xotcl::version < 1.5} {