I've had an eclipse installation that I use for JBoss tools testing running for a long time (months) and i have been able to do updates without problems until last night where I started getting this kind of error:

Cannot complete the install because of a conflicting dependency.
Software being installed: Eclipse SDK 3.6.2.M20110105-0951 (org.eclipse.sdk.ide 3.6.2.M20110105-0951)
Software currently installed: Eclipse IDE for Java EE Developers 1.3.1.20100916-1202 (epp.package.jee 1.3.1.20100916-1202)
Only one of the following can be installed at once:
Equinox Launcher 1.1.0.v20100507 (org.eclipse.equinox.launcher 1.1.0.v20100507)
Equinox Launcher 1.1.1.R36x_v20101122_1400 (org.eclipse.equinox.launcher 1.1.1.R36x_v20101122_1400)
Cannot satisfy dependency:
From: Eclipse IDE for Java EE Developers 1.3.1.20100916-1202 (epp.package.jee 1.3.1.20100916-1202)
To: org.eclipse.epp.package.jee.feature.feature.group [1.3.1.20100916-1202]
Cannot satisfy dependency:
From: Java EE IDE Feature 1.3.1.20100916-1202 (org.eclipse.epp.package.jee.feature.feature.group 1.3.1.20100916-1202)
To: org.eclipse.platform.feature.group [3.6.1.r361_v20100909-9gF78GrkFqw7GrsZnvz0JWNTeb6fue6896L]
Cannot satisfy dependency:
From: Eclipse Platform 3.6.1.r361_v20100909-9gF78GrkFqw7GrsZnvz0JWNTeb6fue6896L (org.eclipse.platform.feature.group 3.6.1.r361_v20100909-9gF78GrkFqw7GrsZnvz0JWNTeb6fue6896L)
To: org.eclipse.rcp.feature.group [3.6.1.r361_v20100827-9OArFLdFjY-ThSQXmKvKz0_T]
Cannot satisfy dependency:
From: Eclipse Product Configuration 1.0.0.M20110105-0951 (org.eclipse.rcp.configuration.feature.group 1.0.0.M20110105-0951)
To: org.eclipse.equinox.launcher [1.1.1.R36x_v20101122_1400]
Cannot satisfy dependency:
From: Eclipse RCP 3.6.1.r361_v20100827-9OArFLdFjY-ThSQXmKvKz0_T (org.eclipse.rcp.feature.group 3.6.1.r361_v20100827-9OArFLdFjY-ThSQXmKvKz0_T)
To: org.eclipse.equinox.launcher [1.1.0.v20100507]
Cannot satisfy dependency:
From: Eclipse SDK 3.6.2.M20110105-0951 (org.eclipse.sdk.ide 3.6.2.M20110105-0951)
To: org.eclipse.rcp.configuration.feature.group [1.0.0.M20110105-0951]

Not sure where such conflict is coming from but wanted to record this in case it evolves to something problematic.

I'm downloading various EPP distros to see if I can reproduce it on a clean setup.