diff --git a/core/07-unpack.php b/core/07-unpack.php
index 067cbf4..cb87b4e 100644
--- a/core/07-unpack.php
+++ b/core/07-unpack.php
@@ -6,14 +6,33 @@
 // ...extract it again
 if(!file_exists($paths->extra_data_directory) || 
 	filemtime(__FILE__) > filemtime($paths->extra_data_directory)) {
+	
+	$error_message_help = "<p>Have you checked that PHP has write access to the directory that <code>index.php</code> is located in (and all it's contents and subdirectories)? Try <code>sudo chown USERNAME:USERNAME -R path/to/directory</code> and <code>sudo chmod -R 0644 path/to/directory; sudo chmod -R +X path/too/directory</code>, where <code>USERNAME</code> is the username that the PHP process is running under.</p>";
+	
 	if(file_exists($paths->extra_data_directory))
 		delete_recursive($paths->extra_data_directory, false);
-	else
-		mkdir($paths->extra_data_directory, 0700);
-	touch($paths->extra_data_directory);
+	else {
+		if(!mkdir($paths->extra_data_directory, 0700)) {
+			http_response_code(503);
+			exit(page_renderer::render_minimal("Unpacking error - $settings->sitename", "<p>Oops! It looks like $settings->sitename couldn't create the extra data directory to unpack additional files to.</p>$error_message_help"));
+		}	
+	}
+		
+	if(!touch($paths->extra_data_directory)) {
+		http_response_code(503);
+		exit(page_renderer::render_minimal("Unpacking error - $settings->sitename", "<p>Oops! It looks like $settings->sitename isn't able to change the last modified time of the extra data directory.</p>$error_message_help"));
+	}
 		
 	$temp_file = tmpfile();
+	if($temp_file === false) {
+		http_response_code(503);
+		exit(page_renderer::render_minimal("Unpacking error - $settings->sitename", "<p>Oops! $settings->sitename wasn't able to create a new temporary file with <code>tmpfile()</code>. Perhaps your server is mis-configured?</p>"));
+	}
 	$source = fopen(__FILE__, "r");
+	if($source === false) {
+		http_response_code(503);
+		exit(page_renderer::render_minimal("Unpacking error - $settings->sitename", "<p>Oops! $settings->sitename wasn't able to open itself (i.e. <code>index.php</code>) for reading. $error_message_help</p>"));
+	}
 	
 	fseek($source, __COMPILER_HALT_OFFSET__);
 	stream_copy_to_stream($source, $temp_file);
@@ -24,5 +43,10 @@ if(!file_exists($paths->extra_data_directory) ||
 	$extractor->open($temp_filename);
 	$extractor->extractTo($paths->extra_data_directory);
 	$extractor->close();
-	fclose($temp_file);
+	if(fclose($temp_file) === false) {
+		http_response_code(503);
+		exit(page_renderer::render_minimal("Unpacking error - $settings->sitename", "<p>Oops! $settings->sitename wasn't able to close the temporary file that it created with <code>tmpfile()</code>. Perhaps your server is mis-configured?</p>"));
+	}
+	
+	unset($error_message_help);
 }