Version:            (using KDE KDE 3.4.0)
Installed from:    RedHat RPMs
OS:                Linux

In script /usr/bin/starkde I found lines

   space_tmp=`df /tmp | xargs | cut -d" " -f11`
   homedir_mount=`df "$HOME" | xargs | cut -d" " -f8`

and then they are called in same script:

if [ $space_tmp -lt 50 ]; then     <- line 24
...
if [ $space_home -lt 25 ]; then   <- line 29

and that causes error lines in .xession-errors file in home directory:

/usr/bin/startkde: line 24: [: 6%: integer expression expected
/usr/bin/startkde: line 29: [: 40%: integer expression expected

I tried to execute space_tmp manually and that returned just 6%. Not an integer!
That occurred in Fedora Core 2 system and Ubuntu. Slackware linux works ok.
Add an check of operating system or change the space_tmp and space_home.

Maybe this is not bug of KDE but operating system.