bwhack,
Sorry you’re seeing this issue.
I noticed one of the errors concerns multiple monitors. There have been problems with multiple monitors on a Macbook when running eclipse. Could you try with the single monitor, and see how that goes? Also, you might want to check the MD5 for the download (the MD5 number is given on the download page), to ensure that the download wasn’t corrupted in some way. If the MD5s are different, please try downloading again.
Are you starting with a fresh workspace? Although this shouldn’t be necessary, it’s worth checking whether that has some effect. Also, with many bundle errors, using the -clean flag can correct those kinds of problems. Click here for a FAQ on using -clean
Let us know if any of these tips work for you. If not, can you clarify what you mean by “whenever I try to do anything”? Do you mean that you don’t get errors in the error log until you try to create a project, edit a file, run an application, explore a database, and so on?
As an additional point, note that you can have multiple releases of MyEclipse installed at once. There is no need to uninstall a previous release.