Index: openacs-4/packages/acs-tcl/tcl/request-processor-procs.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/acs-tcl/tcl/request-processor-procs.tcl,v
diff -u -r1.118.2.4 -r1.118.2.5
--- openacs-4/packages/acs-tcl/tcl/request-processor-procs.tcl	18 Sep 2015 07:33:49 -0000	1.118.2.4
+++ openacs-4/packages/acs-tcl/tcl/request-processor-procs.tcl	11 Oct 2015 17:35:21 -0000	1.118.2.5
@@ -826,9 +826,7 @@
 
     ns_return 500 text/html $rendered_page
 
-    set headers [ns_conn headers]
-    ns_log Error "[ns_conn method] http://[ns_set iget $headers host][ns_conn url]?[ns_conn query]\
-	referred by '$prev_url'\n$error_message"
+    ad_log error $error_message
 }
 
 ad_proc -private rp_path_prefixes {path} {
Index: openacs-4/packages/acs-tcl/tcl/utilities-procs.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/acs-tcl/tcl/utilities-procs.tcl,v
diff -u -r1.140.2.10 -r1.140.2.11
--- openacs-4/packages/acs-tcl/tcl/utilities-procs.tcl	10 Oct 2015 20:16:23 -0000	1.140.2.10
+++ openacs-4/packages/acs-tcl/tcl/utilities-procs.tcl	11 Oct 2015 17:35:21 -0000	1.140.2.11
@@ -4708,7 +4708,29 @@
     return $result
 }
 
+ad_proc -public ad_log {
+    level
+    message
+} {
+    Output ns_log message with detailed context. This function is
+    intended to be used typically with "error" to ease debugging.
+    
+    @param level Severity level such as "error" or "warning".
+    @param message Log message
 
+    @author Gustaf Neumann
+} {
+    set prefix ""
+    if {[ns_conn isconnected]} {
+        set headers [ns_conn headers]
+        append prefix \
+            [ns_conn method] \
+            " http://[ns_set iget $headers host][ns_conn url]?[ns_conn query]" \
+            " referred by '[get_referrer]'\n"
+    }
+    ns_log $level "${prefix}${message}\n[uplevel ad_get_tcl_call_stack]"
+}
+
 # Local variables:
 #    mode: tcl
 #    tcl-indent-level: 4
Index: openacs-4/packages/acs-templating/tcl/tag-init.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/acs-templating/tcl/tag-init.tcl,v
diff -u -r1.39.2.9 -r1.39.2.10
--- openacs-4/packages/acs-templating/tcl/tag-init.tcl	10 Oct 2015 12:26:15 -0000	1.39.2.9
+++ openacs-4/packages/acs-templating/tcl/tag-init.tcl	11 Oct 2015 17:35:22 -0000	1.39.2.10
@@ -141,7 +141,7 @@
 	template::adp_append_code "            ns_cache set ds_page_bits \[ad_conn request\]:error \[lappend __include_errors \[list \"$src\" \$::errorInfo\]\]"
 	template::adp_append_code "        }"
     }
-    template::adp_append_code "        ns_log Error \"Error in include template \\\"\[template::util::url_to_file \"$src\" \"\$__adp_stub\"\]\\\": \$errmsg\n\$::errorInfo\""
+    template::adp_append_code "        ad_log Error \"Error in include template \\\"\[template::util::url_to_file \"$src\" \"\$__adp_stub\"\]\\\": \$errmsg\""
     template::adp_append_code "    }"
     template::adp_append_code "}"
 
@@ -697,7 +697,7 @@
 
   template::adp_append_code "if { \[catch { ad_try { lappend __adp_include_optional_output \[$command\] } ad_script_abort val { } } errmsg\] } {"
   template::adp_append_code "    append __adp_output \"Error in include template \\\"\[template::util::url_to_file \"$src\" \"\$__adp_stub\"\]\\\": \[ns_quotehtml \$errmsg\]\""
-  template::adp_append_code "    ns_log Error \"Error in include template \\\"\[template::util::url_to_file \"$src\" \"\$__adp_stub\"\]\\\": \$errmsg\n\$::errorInfo\""
+  template::adp_append_code "    ad_log Error \"Error in include template \\\"\[template::util::url_to_file \"$src\" \"\$__adp_stub\"\]\\\": \$errmsg\""
   template::adp_append_code "} else {"
   template::adp_append_code "if { \[string trim \[lindex \$__adp_include_optional_output end\]\] ne {} } {"