For error number one, it sounds like you're trying to cast something from a varchar to a date that can't be converted. For example '3 March 2013' can be, but 'Three March 2013' can't. And probably your case is even more extreme. You can try using the ISDATE function to find all the values that are not convertible to datetime. The second error is related. Whatever value is there is outside the accepted range for the data type you're using. Here's some information about the different sizes you can use and how conversions occur.