oclHashcat gui issue
OK, so I downloaded and extracted oclHashcat v0.15 to oclHashcat-gui-0.5.1 and renamed both the old and new files. I have Radeon 4870 cards and Catalyst 13.9. I load up the .hccap file and rockyou.txt, select Straight and WPA/WPA2 and click Start. And this is what I get:

If you have downloaded this 3th party GUI (http://www.md5decrypter.co.uk/hashcat-gui.aspx ) from md5decrypter.co.uk you should ask for help there http://forum.md5decrypter.co.uk/forum8-g...ssion.aspx , right ?

Gui is not supported here, because it is a 3th party software (from md5decrypter.co.uk)

And, other versions of GUI (http://hashcat.net/hashcat-gui/ ) listed here are outdated, therefore either you choose the way to use the md5decrypter.co.uk gui *OR* (recommended) learn to use shell/dos commands and use oclHashcat w/ CLI (command line interface).
OK, thanks.
To add to this, oclHashcat will not work with your Radeon HD 4870 anyway, as the HD 4xxx series does not support OpenCL