diff --git a/app/code/community/Lesti/Fpc/Helper/Data.php b/app/code/community/Lesti/Fpc/Helper/Data.php
index 6fabdc6..1c6ae24 100644
--- a/app/code/community/Lesti/Fpc/Helper/Data.php
+++ b/app/code/community/Lesti/Fpc/Helper/Data.php
@@ -216,7 +216,8 @@ public function canCacheRequest()
         foreach ($missParams as $missParam) {
             $pair = array_map('trim', explode('=', $missParam));
             $key = $pair[0];
-            $param = $request->getParam($key);
+            $param = $this->_paramToString($request->getParam($key));
+
             if ($param && isset($pair[1]) && preg_match($pair[1], $param)) {
                 return false;
             }
@@ -258,4 +259,30 @@ public function getContentType(\Mage_Core_Controller_Response_Http $response)
 
         return 'text/html; charset=UTF-8';
     }
+
+    /**
+     * Transform array parameter to string to avoid error and make correct validation in regexp pattern
+     *
+     * @param mixed $param Input parameter
+     *
+     * @return mixed
+     */
+    protected function _paramToString($param)
+    {
+        if (is_array($param)) {
+            $param = array_reduce(
+                $param,
+                function ($carry, $item) {
+                    if (!is_array($item)) {
+                        return $carry . $item;
+                    }
+
+                    return '';
+                },
+                ''
+            );
+        }
+
+        return $param;
+    }
 }