tomcat startup.sh not working

I download tomcat 6.0.24 and install java set environment variables for java and catalina home and check them they are correct but when i try start tomcat with startup.sh i get setclasspath.sh This file is needed to run this program ,i think it result from permission 开发者_运维技巧and checkfile permissions but every thing ok after i googled and find a solution telling me that raplace basedir and catalinahome enviroment variables in setclasspath.sh with their actual values ,but i want to know what is the source cause of this error.

By the way,if a kill tomcat and run startup.sh it give this output but tomcat actually running ,when i try localhost:8080

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enviroment variables wrong in my case catalina_home sorry for post