bug on "My Sites" widget in dashboard.

If I suppress the "my sites" widget", it works fine.
See screenshots attached. The dm version on which I get this error is 5.4.1-I20110125_0115 (client project, thus this need a patch, or any temp. A solution like automatically desactivate the mysites widget - which is not needed in the project - would be OK. Nothing appears in the logs.