Error during digital signature in the acrobat XI

Hello,

I work for a company named Construtivo.com do Brasil.

I'm  trying to sign some documents in Acrobat Pro XI version 11.0.7  but I  receive the error below every time that I try to validate the signatures

Error during signature verification. 

Error encountered while validating: 

Error encountered while BER decoding:

I have contacted the support team adobe.com and follow all the tips they gave me, but the error is still displayed

I 'm not expert in digital signature and acrobat,but I believe that I already have checked almost everything as follow:

The digital certification is valid

The driver of token certification installed is ok.

The certificate is in the trust certification list.

I made several tests in computers with Windows 7 (32 and 64)

Thank you in advance and forgive me for my bad english.

Fabiano Oliveira