Multiple eclipse problems suddenly appeared

I am using eclipse 2.1 with a tomcat plug-in. It was been working fine for a month or more. Now suddenly I am having multiple problems. If I try to use <ctrl>,<shift><O> I get
"The resource is not on the build path of a java project"
When I try to open a jsp by clicking and selecting open I get
"Can not open default editor on <page name.jsp>.
Text editor does not have a document provider"
If I go to <Project><Properties> I get
no property pages for <project name>

I have three projects and all are having the same problem. I was using at least some of these features as late as yesterday. The only thing I have done lately was to bring in a classes12.jar file from one project to another but even after that the <ctrl>,<shift><O> was working. That is not to say that the other features were or were not working. I just discovered things were hosed this morning. Any ideas?

Thanks for the help.

I remember i had a similar issue earlier.

You have 2 options....

1) you should find a ".config" directory under your <workspace directory>\.metadata folder. Delete that directory and restart
eclipse .

2) Upgrade to later version..

Vijay

Thanks V,
I took a third option and re-installed. Seemed to have worked but I am guessing deleting that bad file would have been wiser.