i have exactly the same problem:
An error occurred while collecting items to be installed
session context was:(profile=PlatformProfile, phase=org.eclipse.equinox.internal.provisional.p2.engine.phases.Collect, operand=, action=).
Problems downloading artifact: osgi.bundle,net.sourceforge.sqlexplorer,3.5.1.v20091018.
MD5 hash is not as expected. Expected...
2009-10-22 22:39:55 UTC in Eclipse SQL Explorer [RCP/Plugin]
