--- groupinfo-old.c	2006-03-27 10:19:37.000000000 +0200
+++ groupinfo.c	2006-03-27 10:36:33.000000000 +0200
@@ -36,6 +36,8 @@
     DWORD rv;
     char *pos;
 
+    if (!groupname)
+        return APR_EINVAL;
     if (pos = strchr(groupname, '/')) {
         domain = apr_pstrndup(p, groupname, pos - groupname);
         groupname = pos + 1;