For those of you that haven’t read about this at Techmundo or at E-Series read on:
If you get a certificate error when attempting to install 3rd party software on your S60 3rd Edition smartphone (Nokia E61/E61 or other), it means that you haven’t enabled installation of unsigned SIS files. Go to Tools> App. Manager, choose Options> Settings and set Software installation to All and Online certif. check to Off.

Remember that this is like removing one lock from a door.
But I think that this can’t really harm you because you choose what you download.
March 19, 2007 at 2:30 pm
yep already tried that but still have the problem when i try to install any software. I recently updated my Nokia phone software via the nokia updater and this is when all this started.
No matter what i try to install be it off the CD that came with the phone i get an error saying something along the lines of certificate may not be valid and to check my date and time on teh mobile?.
Any other tips for me please.
April 3, 2007 at 1:20 pm
I have the same problem.. started when i updated my software!
any tips woudl be great
thanks
April 28, 2007 at 4:18 am
Peace people
We love you
May 23, 2007 at 2:58 pm
NED DOWNLOADS
May 23, 2007 at 2:59 pm
NEED DOWNLOADS
May 23, 2007 at 2:59 pm
GIVEME