Eclipse 3.4.x sucks! And, the latest Spring IDE and the new arrived SpringSource dm Server Tool work better on Eclipse 3.3.x. So the following should be the most suitable environment for Spring development currently:
Eclipse SDK 3.3.2
EMF-XSD-SDO 2.3.2
GEF 3.3.2
DTP 1.5.2
WTP 2.0.3
AJDT 1.5.3
Spring IDE 2.2.0
Update Site: http://dist.springframework.org/release/IDE
Remember to only select those components really needed. Keep your environment simpler and cleaner while efficient.
SpringSource dm Server Tool 1.1.0
Update Site: http://static.springsource.com/projects/sts-dm-server/update