[plt-scheme] What does it mean when some buttons and languages are missing?

My computing center just upgraded the Scheme installation on our main 
(Linux-based) Web server from 207 to 301.  I don't expect to be using 
DrScheme directly on that machine very often -- mostly just running 
cgi scripts from Web pages -- but it's nice to have it available for 
debugging said cgi scripts.

When I started it up (as an X client), I noticed that there was no 
"Step" or "Check Syntax" button (only "Run" and "Stop"), and that 
many of the languages I expected weren't there (only R5RS, Textual 
MzScheme, Graphical MrEd, Pretty Big, Expander, and (module...)). 
Are these add-ons not implemented for Linux, or did the 
computing-center people somehow fail to install them, or what?
-- 
							Stephen Bloch
							Math/CS Dept
 
Adelphi University
 
sbloch at adelphi.edu