Yes, I have seen this signature error since a week ago,
I first thought was that something had gone wrong when I upgraded to Verizonís new 4.1 OS, but that wasnít the case. There is something wrong with the download site.
orgullo im from mexico too.. i just got the 8700 yesterday i downloaded the messenger from the blackberry help page.. and it worked out perfectly.. on the other hand.. i downloaded the MSN client.. and i couldnt get through the connexion.. it said something about cheking the internet settings..
then i used another APN : internet.itelcel.com.. and it worked out well
but im affraid i'll be charged for switching the APN