The upgrade document says "Move or copy the following files and directories... Any themes or plugins you had installed"
Is this the case when upgrading from 1.5.3 to 2.1.4? That's what I did and now activating a plugin after the upgrade kills omeka until I delete the plugin folder. Thanks --Nicholas
Is this the case when upgrading from 1.5.3 to 2.1.4?
No. Plugins need to be listed as being "2.0 compatible" to work with Omeka 2.x. The copies of plugins you had in 1.x are very unlikely to work when you change to 2.x, but you might be able to download newer versions to replace them.
Step 2, earlier in the instructions, tries to make that clear. I just edited it to make the point about plugin compatibility a little more clear.