Thanks for pointing out this issue. I've corrected it and in the course of it also noticed and corrected another problem in the case of filenames that have more than one (.) in them.
This fix will be included in the next release. You can apply it now by downloading the below file (contains only one replacement file) and overwriting the
load.php included in the root folder of GDE 2.5.3.
If you send me a support request via the "Support" tab I can also send you a custom build directly that will install this fix automatically.