$ java -jar /home/public/jmahu/selenium-server.jar -interactive
10:54:19.957 INFO - Java: Sun Microsystems Inc. 1.7.0-b24
10:54:19.959 INFO - OS: Linux 2.6.24.5-desktop-2mnb i386
10:54:19.962 INFO - v1.0-beta-1 [2201], with Core v1.0-beta-1 [1994]
10:54:20.099 INFO - Version Jetty/5.1.x
10:54:20.102 INFO - Started HttpContext[/selenium-server/driver,/selenium-server/driver]
10:54:20.104 INFO - Started HttpContext[/selenium-server,/selenium-server]
10:54:20.105 INFO - Started HttpContext[/,/]
10:54:20.115 INFO - Started SocketListener on 0.0.0.0:4444
10:54:20.116 INFO - Started org.mortbay.jetty.Server@18fb1f7
Entering interactive mode... type Selenium commands here (e.g: cmd=open&1=http://www.yahoo.com)
cmd=getNewBrowserSession&1=*firefox&2=http://google.com
10:54:26.519 INFO - ---> Requesting http://localhost:4444/selenium-server/driver?cmd=getNewBrowserSession&1=*firefox&2=http://google.com
10:54:26.641 INFO - Checking Resource aliases
10:54:26.644 INFO - Command request: getNewBrowserSession[*firefox, http://google.com] on session null
10:54:26.645 INFO - creating new remote session
10:54:26.745 WARN - GET /selenium-server/driver/?cmd=getNewBrowserSession&1=*firefox&2=http://google.com HTTP/1.1
java.lang.RuntimeException: Firefox couldn't be found in the path!
Please add the directory containing 'firefox-bin' to your PATH environment
variable, or explicitly specify a path to Firefox like this:
*firefox /blah/blah/firefox-bin
[...]

on Mandriva Linux the firefox binary is called "firefox" and is in "/usr/bin" (which is naturally in the PATH)
more precisely the file "/usr/bin/firefox" is a script calling the real firefox binary which is in "/usr/lib/firefox-<version>/"
but this binary is called "mozilla-firefox-bin" and cannot be called directly.