Normally you can't install RMS on shared hosting, but considering you have ssh access and are allowed to install things, it may be possable. You could install and run muds and various other stuff so it won't hurt to try. But no garentees.
Anyhow. JAVA_HOME=/jre1.6.0_13; << is it correct?
No, that is not correct. Must be full path. /home2/username/jre1.6.0_13
But that is not the cause of your error.
Bad interpreter means the shell the script is trying to use is not installed. Or the path to it is not the same as specified in the script. The first line shows the shell. #!/bin/bash
Thus bash must be on the server.
Could also be you forgot to set 777 permissions on the *.sh scripts as per the instructions.
If its because bash is not installed then you will not be able to install it. Shells have to be installed by the server admins.
echo $SHELL will tell you what shell your currently using.
But even if you manage to get it installed, you may run into other issues such as firewalls.