First off, the use of Pimp my wii is highly discouraged here at wiihacks. In fact, we often call it brick my wii. The reason for this is that Pimp my wii gives the user the false idea that the latest version is always the best. This is very not true. For example, some people (including a mod/admin here) have reported that heir hdd won't work with the new cIOSX rev21, while it does work with older revisions. For this reason, we recommend cIOS38 rev17 for most users, because it is known to be stable. Besides, no game I know of requires the use of a higher revision. Also, you have rev1008 of USB Loader GX, which is still a beta (=test) version. It is no wonder to me that some of your games black screen.
I recommend you use the softmod any wii guide in my sginature to get your softmod in a normal state again. After that, use the Easy installer of USB Loader GX, which will install the latest stable version of USB Loader GX.