diff --git a/Classes/PHPExcel/Reader/Excel2003XML.php b/Classes/PHPExcel/Reader/Excel2003XML.php
index 0f96c000..a25d0373 100644
--- a/Classes/PHPExcel/Reader/Excel2003XML.php
+++ b/Classes/PHPExcel/Reader/Excel2003XML.php
@@ -162,10 +162,11 @@ class PHPExcel_Reader_Excel2003XML implements PHPExcel_Reader_IReader
 	}
 
 	/**
-	 * Can the current PHPExcel_Reader_IReader read the file?
+	 *	Can the current PHPExcel_Reader_IReader read the file?
 	 *
-	 * @param 	string 		$pFileName
-	 * @return 	boolean
+	 *	@param 	string 		$pFileName
+	 *	@return 	boolean
+	 *	@throws Exception
 	 */
 	public function canRead($pFilename)
 	{
diff --git a/Classes/PHPExcel/Reader/Excel2007.php b/Classes/PHPExcel/Reader/Excel2007.php
index 07b9a853..061c22d0 100644
--- a/Classes/PHPExcel/Reader/Excel2007.php
+++ b/Classes/PHPExcel/Reader/Excel2007.php
@@ -177,30 +177,31 @@ class PHPExcel_Reader_Excel2007 implements PHPExcel_Reader_IReader
 	}
 
 	/**
-	 * Can the current PHPExcel_Reader_IReader read the file?
+	 *	Can the current PHPExcel_Reader_IReader read the file?
 	 *
-	 * @param 	string 		$pFileName
-	 * @return 	boolean
+	 *	@param 	string 		$pFileName
+	 *	@return 	boolean
+	 *	@throws Exception
 	 */
 	public function canRead($pFilename)
 	{
-		// Check if zip class exists
-		if (!class_exists('ZipArchive')) {
-			return false;
-		}
-
 		// Check if file exists
 		if (!file_exists($pFilename)) {
 			throw new Exception("Could not open " . $pFilename . " for reading! File does not exist.");
 		}
 
+		// Check if zip class exists
+		if (!class_exists('ZipArchive')) {
+			throw new Exception("ZipArchive library is not enabled");
+		}
+
 		$xl = false;
 		// Load file
 		$zip = new ZipArchive;
 		if ($zip->open($pFilename) === true) {
 			// check if it is an OOXML archive
 			$rels = simplexml_load_string($this->_getFromZipArchive($zip, "_rels/.rels"));
-			if ($rels) {
+			if ($rels !== false) {
 				foreach ($rels->Relationship as $rel) {
 					switch ($rel["Type"]) {
 						case "http://schemas.openxmlformats.org/officeDocument/2006/relationships/officeDocument":
diff --git a/Classes/PHPExcel/Reader/Gnumeric.php b/Classes/PHPExcel/Reader/Gnumeric.php
index 7a946813..d151dcea 100644
--- a/Classes/PHPExcel/Reader/Gnumeric.php
+++ b/Classes/PHPExcel/Reader/Gnumeric.php
@@ -179,23 +179,24 @@ class PHPExcel_Reader_Gnumeric implements PHPExcel_Reader_IReader
 	}
 
 	/**
-	 * Can the current PHPExcel_Reader_IReader read the file?
+	 *	Can the current PHPExcel_Reader_IReader read the file?
 	 *
-	 * @param 	string 		$pFileName
-	 * @return 	boolean
+	 *	@param 	string 		$pFileName
+	 *	@return 	boolean
+	 *	@throws Exception
 	 */
 	public function canRead($pFilename)
 	{
-		// Check if gzlib functions are available
-		if (!function_exists('gzread')) {
-			return false;
-		}
-
 		// Check if file exists
 		if (!file_exists($pFilename)) {
 			throw new Exception("Could not open " . $pFilename . " for reading! File does not exist.");
 		}
 
+		// Check if gzlib functions are available
+		if (!function_exists('gzread')) {
+			throw new Exception("gzlib library is not enabled");
+		}
+
 		// Read signature data (first 3 bytes)
 		$fh = fopen($pFilename, 'r');
 		$data = fread($fh, 2);
diff --git a/Classes/PHPExcel/Reader/OOCalc.php b/Classes/PHPExcel/Reader/OOCalc.php
index 05657721..a3e193f0 100644
--- a/Classes/PHPExcel/Reader/OOCalc.php
+++ b/Classes/PHPExcel/Reader/OOCalc.php
@@ -169,23 +169,24 @@ class PHPExcel_Reader_OOCalc implements PHPExcel_Reader_IReader
 	}
 
 	/**
-	 * Can the current PHPExcel_Reader_IReader read the file?
+	 *	Can the current PHPExcel_Reader_IReader read the file?
 	 *
-	 * @param 	string 		$pFileName
-	 * @return 	boolean
+	 *	@param 	string 		$pFileName
+	 *	@return 	boolean
+	 *	@throws Exception
 	 */
 	public function canRead($pFilename)
 	{
-		// Check if zip class exists
-		if (!class_exists('ZipArchive')) {
-			return false;
-		}
-
 		// Check if file exists
 		if (!file_exists($pFilename)) {
 			throw new Exception("Could not open " . $pFilename . " for reading! File does not exist.");
 		}
 
+		// Check if zip class exists
+		if (!class_exists('ZipArchive')) {
+			throw new Exception("ZipArchive library is not enabled");
+		}
+
 		// Load file
 		$zip = new ZipArchive;
 		if ($zip->open($pFilename) === true) {
diff --git a/Classes/PHPExcel/Reader/SYLK.php b/Classes/PHPExcel/Reader/SYLK.php
index 97d98506..12a60168 100644
--- a/Classes/PHPExcel/Reader/SYLK.php
+++ b/Classes/PHPExcel/Reader/SYLK.php
@@ -87,10 +87,11 @@ class PHPExcel_Reader_SYLK implements PHPExcel_Reader_IReader
 	}
 
 	/**
-	 * Can the current PHPExcel_Reader_IReader read the file?
+	 *	Can the current PHPExcel_Reader_IReader read the file?
 	 *
-	 * @param 	string 		$pFileName
-	 * @return 	boolean
+	 *	@param 	string 		$pFileName
+	 *	@return 	boolean
+	 *	@throws Exception
 	 */
 	public function canRead($pFilename)
 	{