I had to put updated software on my Telstra E51 the other day because Telstra has upgraded the mobile equipment in the field and the E51 would reset all the time (I would get a white screen and then it reset, white screen and reset over and over)
Once I updated the NokiaE51 and all was working again I plugged the Nokia E51 in the PC and the Nokia PC Suite started up. It said I
needed to install MMSsync on the NokiaE51 for the messaging to work properly.
But, of course, it wasn’t that easy. I accepted the install on the phone but it gave me a “MMSSync Expired Certificate” error. Retried and the same happened. So how to install MMSsync through the Nokia PC Suite in Nokia E51
So I thought about it a bit and this is how you fix the problem and get MMSsync to install on the Nokia E51 (and probably E71, E61, E52)
The fix I worked out is before you update your phone you have to set the E51 phone date to a date between October 2006 and October 2011. I just changed the year to 2010 and left the time and date the same. After the date is changed install MMSSync, it will install for sure. Then remember to put the correct date back after the install.
All done. Simple.
goldcoaster 
I’ve deleted my certificate so i want it again.
Works on n95 8gb too. Ta.
I’ll try it. But there is a errfr
“certificate erro” contact your service perovider” what to do
keep up de simple gd work…
just follow these instructions and you should be fine with the expired certificate error on Nokia E63 when installing MMSsync by PC Suite