since update to Zend 8 20110515 do i have the same problems.
i switch an open file (workspace) it will popup the error Message "Processing Dirty Regions" with the details:
An internal error occurred during: "Processing Dirty Regions".
org.eclipse.dltk.ast.references.VariableReference cannot be cast to org.eclipse.php.internal.core.compiler.ast.nodes.ArrayCreation
please help, before the update it works ok.