--- squid-3.1.10-orig/src/logfile.cc	2010-12-22 00:46:56.000000000 -0500
+++ squid-3.1.10/src/logfile.cc	2011-02-03 14:04:57.390415640 -0500
@@ -128,6 +128,9 @@
                        "\tThe parent directory must be writeable by the\n"
                        "\tuser '%s', which is the cache_effective_user\n"
                        "\tset in squid.conf.", path, Config.effectiveUser);
+            } else if (EISDIR == errno && fatal_flag) {
+                fatalf("Cannot open '%s' because\n"
+                       "\tit is a directory, not a file.\n", path);
             } else {
                 debugs(50, 1, "logfileOpen: " << path << ": " << xstrerror());
                 return NULL;