I was upgrading the tomcat in my eclipse from version 6 to 7. Servers were added, old servers were removed. Tomcat 6 installed. But the server is not starting because of the following error.
Target runtime Apache Tomcat v6.0 is not defined. <project name> Unknown Faceted Project Problem
It keeps my old server entry for the project.
We need to right click on the project, properties and Targeted Runtimes. Uncheck the old entry and enable the new entry. This should solve this error.
Targeted Runtimes
Still server is facing some other issue. Need to check up.
JavaShine 
excellent working for me
Excellent! It worked for me!
thankuuu this worked for me
got the same issue here and thanks a lot your solution works! you saved my days
gr8:) thanks for the help… my project is errorfree now 🙂 🙂
Great. You are welcome
Excellent.. Thanks for the post.
Thanks for visiting.
thanks a lot….. it helped… 🙂
Thanks for making effort to give your feedback
A perfect hint !
Thanks mario
Excellent… thanks a lot…
Thanks Hari
Thx, it solved my compilation problem.
Good to know that.
Great! enjoy
It worked for me also. Thx!
thanq for giving information