sounds like you're missing the Qt libraries, it's something you can download. If you check the FGLRX requirements beforehand. Here are those mentioned on the release notes.
Try to install most of the below, chances are it will pick up additional stuff like Qt as dependencies.
The following packages must be installed in order for the AMD Catalyst™ Proprietary Linux Graphics Driver to install and work optimally:
gimp-help-en
gimp-help-common
XFree86-Mesa-libGL
libstdc++
libgcc
XFree86-libs
fontconfig
freetype
zlib
gcc
Some of these packages (namely gimp-help-common, XFree86-Mesa-libGL, libgcc, and XFree86-libs) can't be found by pacman so do I need to install them differently?
EDIT: I'm going to assume that gcclib is gcc-multilib but I still don't know about the rest
I did some more research and I found out that the reason why it wasn't working was that I didn't have gt4 installed. Now that I've got it installed it works fine but it gives me the error:
libpng warning: iCCP: known incorrect sRGB profile
Though I am still curious about the packages that pacman couldn't find but forget the thing I said about gcc-multilib being libgcc. That was retarded