The End-to-End Error count reflects problems in the data path through the drive's cache RAM (SDRAM). It appears that Samsung doesn't treat this attribute as seriously as other HDD manufacturers. Seagate, for example, allows for only one error before this attribute falls below its threshold.
See
http://en.wikipedia.org/wiki/S.M.A.R.T.
The UDMA CRC Error Count may reflect a compatibility problem with the motherboard's southbridge. For example, certain SpinPoints wouldn't get along with AMD's SB850 chipset and required a firmware update. Intel's P67/H67 chipset was afflicted with a bug that would result in the slow deterioration of the SATA port.
Some drives have a jumper that limits the SATA link rate. Others can limit the interface speed by way of a utility provided by the manufacturer.