When attempting to backup my new Curve I received an error stating that the device did not recognise some content. Following a bit of investigation I narrowed it down to having an entry in the voicemail field within the phone options screen. I've got around this by removing the entry, creating a contact called Voicemail and assigning that to the 1/W key.
This was found using version 4.2.2.14 of Desktop Manager and App Version 4.2.2.114 on a handset that was supplied unlocked through O2 in the UK.