Thanks everybody for the replies. I might be wrong but I tried stardict but it didn't work with OS2006. It can be installed but there is no way to run it. Let me know if you know how to make it work with OS2006.
I also tried Stardict, in my case to get an English-Japanese dictionary, but the operation was exceedingly slow, so slow as to be near useless. Sorry to say that I haven't found any other non-webbased alternatives.