Exception in thread "main".. launching a .jar from Linux (Slackware 10) desktop

[Rory Jakes]

I downloaded a .jar file (Arachnophilia.jar) and can launch the
application from the command line in an xterm with the following:
java
-jar Arachnophilia.jar if I am in the /downloads/Arachnophilia
directory.

I need to be in the directory containing the jar file. I created a
shell script called arach. I placed the script (arach) in the
directory containing the .jar file (Arachnophilia.jar) in my $PATH$
in
/etc/profile. I get the error (below) when I try to run arach unless
I
am physically in the arach directory (downloads/Arachnophilia). I
eventually want to create an icon on my desktop that points to
/downloads/Arachnophilia/arach

rjakes@HOME:~$ arach
-bash: /downloads/Arachnophilia/arach: No such file or directory
rjakes@HOME:~$ arach
Exception in thread "main" java.util.zip.ZipException: No such file
or directory
at java.util.zip.ZipFile.open(Native Method)
at java.util.zip.ZipFile.<init>(ZipFile.java:112)
at java.util.jar.JarFile.<init>(JarFile.java:127)
at java.util.jar.JarFile.<init>(JarFile.java:65)

Thank you in advance,
Rory Jakes