Index: openacs-4/packages/acs-datetime/tcl/acs-datetime-procs.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/acs-datetime/tcl/acs-datetime-procs.tcl,v
diff -u -r1.5 -r1.5.2.1
--- openacs-4/packages/acs-datetime/tcl/acs-datetime-procs.tcl	14 Sep 2002 17:30:43 -0000	1.5
+++ openacs-4/packages/acs-datetime/tcl/acs-datetime-procs.tcl	13 Mar 2003 02:18:58 -0000	1.5.2.1
@@ -242,7 +242,12 @@
       set month [expr $month + 1]
     }
 
-    return [clock format [clock scan $year-$month-01] -format %Y-%m-%d]
+    # jarkko: added this check to avoid calendars bombing when prev month goes
+    # beyond borders
+    if {[catch {set next_month [clock format [clock scan $year-$month-01] -format %Y-%m-%d]} err]} {
+	return ""
+    }
+    return $next_month
 }
 
 ad_proc dt_prev_month {
@@ -258,7 +263,13 @@
       set month [expr $month - 1]
     }
 
-    return [clock format [clock scan $year-$month-01] -format %Y-%m-%d]
+    # jarkko: added this check to avoid calendars bombing when prev month goes
+    # beyond borders
+    if {[catch {set prev_month [clock format [clock scan $year-$month-01] -format %Y-%m-%d]} err]} {
+	return ""
+    }
+
+    return $prev_month
 }
 
 ad_proc dt_next_month_name {
@@ -274,7 +285,13 @@
       set month [expr $month + 1]
     }
 
-    return [clock format [clock scan $year-$month-01] -format %B]
+    # jarkko: added this check to avoid calendars bombing when next month goes
+    # beyond borders
+    if {[catch {set next_name [clock format [clock scan $year-$month-01] -format %B]} err]} {
+	return ""
+    }
+
+    return $next_name
 }
 
 ad_proc dt_prev_month_name {
@@ -290,7 +307,14 @@
       set month [expr $month - 1]
     }
 
-    return [clock format [clock scan $year-$month-01] -format %B]
+    # jarkko: added this check to avoid calendars bombing when prev month goes
+    # beyond borders
+
+    if {[catch {set prev_name [clock format [clock scan $year-$month-01] -format %B]} err]} {
+	return ""
+    }
+
+    return $prev_name
 }
 
 ad_proc -public dt_widget_datetime {