Hey - no problems. I only manage to provide, somewhat, quick responses because I am fortunate enough to have a job where computer use is a must.
"Arch" is short-form for "architecture" - it refers to the design of your processor (CPU). All you need to know, is that there are different processor architectures out there, and what their names are:
"i386" - Intel-class processors. i386 works on almost everything - it can also be referred to as "x86", but the two names are NOT synonymous.
"PPC" or "PowerPC" - For Apple computers before they switched to Intel processors.
"sparc" and "sparc64" - 32- and 64-bit Sun Microsystems SPARC processors.
"amd64" - 64-bit AMD Turion processors.
"x86_64" - Intel single- and dual-core 64-bit processors.
The only time I have ever heard of "arch problems" was when somebody was using an earlier version of a 64-bit Linux distribution.
Could you please open Konsole again, and post the output of the following command:
Also, I would suggest trying to install the package from the command-line:
$ sudo aptitude install libsdl-mixer