If memory on a DOS/ Windows machine is configured improperly, or there is a driver conflict, the error message "Not enough memory to run application, please close some applications and try again" will appear. One particular instance is this:
Config.sys Autoexec.bat
C:\\dos\\setver.exe Pcache
C:\\windows\\himem.sys C:\\windows\\smartdrv.exe
dos=high Prompt $p$g
files=10 Set Mouse=C:\\mouse
stacks=9,256 c:\\mouse\\mouse.com
Path ....
Set temp=c:\\dos
Removing the Pcache line in the Autoexec.bat, increasing files to 40, and adding a Buffers=20 line allowed ClarisWorks to run.