diff -purN cacherouter-rc1/engines/file.php cacherouter-rc1-filesize-patch/engines/file.php
--- cacherouter-rc1/engines/file.php	2009-09-05 06:03:25.000000000 -0700
+++ cacherouter-rc1-filesize-patch/engines/file.php	2009-09-18 09:32:46.000000000 -0700
@@ -43,9 +43,12 @@ class fileCache extends Cache {
       if (file_exists($cache_file)) {    
         if ($fp = fopen($cache_file, 'r')) {
           if (flock($fp, LOCK_SH)) {
-            $data = @fread($fp, filesize($cache_file));
-            flock($fp, LOCK_UN);
-            $cache = unserialize($data);
+            if (file_exists($cache_file)) {
+              $fs = filesize($cache_file);
+              $data = @fread($fp, $fs);
+              flock($fp, LOCK_UN);
+              $cache = unserialize($data);
+            }
           }
           fclose($fp);
         }
@@ -261,9 +264,12 @@ class fileCache extends Cache {
         if (file_exists($file->filename)) {    
           if ($fp = @fopen($file->filename, 'r')) {
             if (flock($fp, LOCK_SH)) {
-              $data = @fread($fp, filesize($file->filename));
-              flock($fp, LOCK_UN);
-              $cache = unserialize($data);
+              if (file_exists($cache_file)) {
+                $fs = filesize($cache_file);
+                $data = @fread($fp, $fs);
+                flock($fp, LOCK_UN);
+                $cache = unserialize($data);
+              }
             }
             fclose($fp);
             if ($cache->expire != CACHE_PERMANENT && $cache->expire <= time()) {