diff --git a/Repositories/statistics/scripts/eprints-usage_src.php b/Repositories/statistics/scripts/eprints-usage_src.php
index 484dafc..b4cc3a1 100755
--- a/Repositories/statistics/scripts/eprints-usage_src.php
+++ b/Repositories/statistics/scripts/eprints-usage_src.php
@@ -557,7 +557,7 @@
 			/* NJS 2007-01-26
 			   Check whether this is a bot reference.
 			*/
-			$user_agent = $matches[4];
+			$user_agent = count($matches) > 4 ? $matches[4] : '';
 			$found_country = FALSE;
 			foreach ($bot_patterns as $id => $patterns)
 			{