Index: openacs-4/packages/acs-tcl/tcl/apm-install-procs.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/acs-tcl/tcl/apm-install-procs.tcl,v
diff -u -N -r1.126.2.19 -r1.126.2.20
--- openacs-4/packages/acs-tcl/tcl/apm-install-procs.tcl	18 Nov 2021 19:13:46 -0000	1.126.2.19
+++ openacs-4/packages/acs-tcl/tcl/apm-install-procs.tcl	5 Dec 2021 15:42:02 -0000	1.126.2.20
@@ -1026,8 +1026,10 @@
             -arg_list [list from_version_name $upgrade_from_version_name to_version_name $version(name)]
     }
 
-    # Flush the installed_p cache
-    acs::misc_cache flush apm_package_installed-$package_key
+    if {[info commands ::acs::misc_cache] ne ""} {
+        # Flush the installed_p cache
+        acs::misc_cache flush apm_package_installed-$package_key
+    }
 
     return $version_id
 }
@@ -1541,7 +1543,8 @@
     @param version_id The id of the version to be enabled.
 } {
     db_exec_plsql apm_package_version_enable {}
-    acs::misc_cache flush apm_package_enabled-[apm_package_key_from_version_id $version_id]
+    acs::try_cache acs::misc_cache flush \
+        apm_package_enabled-[apm_package_key_from_version_id $version_id]
     apm_callback_and_log $callback  "<p>Package enabled."
 }
 
@@ -1552,7 +1555,8 @@
     @param version_id The id of the version to be disabled.
 } {
     db_exec_plsql apm_package_version_disable {}
-    acs::misc_cache flush apm_package_enabled-[apm_package_key_from_version_id $version_id]
+    acs::try_cache acs::misc_cache flush \
+        apm_package_enabled-[apm_package_key_from_version_id $version_id]
     apm_callback_and_log $callback  "<p>Package disabled."
 }