Java SE (Java Platform, Standard Edition)

Hello
Im getting sick over trying to install that javax.comm package over the last night.
Here is what i do:

- Download javacomm20-win32
- win32com-dll to /bin
- javax.comm.properties to /lib
- comm.jat to /lib

I find a jdk1.5.0 and a jre1.5.0 folder on my XP-Machine.
I `ve choosen the jdk folder but also tried the jre. On different threads here, its also lib/ext instead of /lib - i tried that too, even when i the doucumentation its /lib.
Is there a way to include this package into my library such as a "normal" package like javax.swing - the way i can use it the common was? What does "javax.comm.properties needs to be installed" mean? How can i install a file like that and where do i do that? On a other forum, someone added lines to that file. I use it the state i downloaded it, because the docu doenst tell me anything about makong changes, is this correct?
When starting eclipse, the package and his classes cant be resolved.

Im pretty new to that - Could someone give me a comment about my problem? It would be really great!