It was just a random guess, since sometimes systems that only expect RSA keys to exist give weird messages when they can't parse other kinds of keys.
BER is the encoding format used for most certificate files, so an error with not understanding the BER data means that it doesn't understand something. Though maybe it's not understanding that the certificate doesn't have a OCSP URL embedded anymore. Again, just wild guesses, it's hard to know what your system is meaning with so little to go on.