Lots of rx_errors on e100 based NICs after upgrade from RHEL-5 to RHEL-6

Issue

Applications running on RHEL6 after upgrade from RHEL 5 are suddenly experiencing network troubles.

# yum install -y sos
Loaded plugins: product-id
http://servidor/XXX/XXX/repos/aprot/repodata/b319e85da3965a7910d578de824f86d417569a19edeafb7def5de52613575526-primary.sqlite.bz2: [Errno 12] Timeout on http://servidor/XXX/repos/aprot/repodata/b319e85da3965a7910d578de824f86d417569a19edeafb7def5de52613575526-primary.sqlite.bz2: (28, 'Operation too slow. Less than 1 bytes/sec transfered the last 30 seconds')

ethtool shows lots of rx_errors.

# ethtool -S eth0
NIC statistics:
     rx_packets: 67126
     tx_packets: 19040
     rx_bytes: 13444434
     tx_bytes: 6962901
     **rx_errors: 7021**
     tx_errors: 0
     rx_dropped: 0
     tx_dropped: 0
     multicast: 0
     collisions: 0
     rx_length_errors: 469
     rx_over_errors: 0
     rx_crc_errors: 5878
     rx_frame_errors: 674
     rx_fifo_errors: 0
     rx_missed_errors: 0
     tx_aborted_errors: 0
     tx_carrier_errors: 0
     tx_fifo_errors: 0
     tx_heartbeat_errors: 0
     tx_window_errors: 0
     tx_deferred: 0
     tx_single_collisions: 0
     tx_multi_collisions: 0
     tx_flow_control_pause: 0
     rx_flow_control_pause: 0
     rx_flow_control_unsupported: 0
     tx_tco_packets: 0
     rx_tco_packets: 0