diff --git a/modules/config.xqm b/modules/config.xqm
index 6f25a218b9195e575e000a7da12de2b4d9144743..ab1c62394dedef689f8d0bf1c7fee5c48171e3ec 100644
--- a/modules/config.xqm
+++ b/modules/config.xqm
@@ -19,13 +19,13 @@ declare variable $config:app-root :=
         (: strip the xmldb: part :)
         if (starts-with($rawPath, "xmldb:exist://")) then
             if (starts-with($rawPath, "xmldb:exist://embedded-eXist-server")) then
-                substring($rawPath, 36)
+                substring-after($rawPath, "xmldb:exist://embedded-eXist-server")
             else
-                substring($rawPath, 15)
+                substring-after($rawPath, "xmldb:exist://")
         else
             $rawPath
     let $path := substring-before($modulePath, "/modules")
-    return if (starts-with($path, "null")) then substring($path, 3) else $path;
+    return if (starts-with($path, "null")) then substring-after($path, "null") else $path;
 
 declare variable $config:data-root := $config:app-root || "/" || config:get("project-id");
 declare variable $config:repo-descriptor := doc(concat($config:app-root, "/repo.xml"))/repo:meta;