If you have defined a data node type which has its root on level > 1 you'll get a NPE when trying to delete the item type.

{{2012-05-05 07:04:18,637 ERROR fo.magnolia.module.data.commands.TypeDeleteCommand: cannot do delete
java.lang.NullPointerException
at info.magnolia.module.data.commands.TypeDeleteCommand.itemsExist(TypeDeleteCommand.java:119)}}

This is caused by the use of (deprecated) .getChildByName() which of course does not work for something like "/customer/products".

The attached patch uses ContentUtil.getContent(repository, path) instead and therefore also works with nested root nodes.