OK, thank you very much for replying!!!

so, I've changed my approach. I've manually added the column in source file and on destination sql table as smallint.

My flow is:

Excel Source -> Derived Column -> Data Conversion -> OLE DB Destination and my error is now only at the last data flow task.

1. Excel Source maps FiscalYearNumber

2. Derived Column does conversion so that for a given empty column it will supply the value "2012" FiscalYearNumber==”0”? “2012”: [FiscalYearNumber]

3. Data Conversion converts data type for this column to two-byte signed integer.

4. OLE Destination goes red with the following error:

[OLE DB Destination [684]] Error: There was an error with input column "Copy of FiscalYearNumber" (1170) on input "OLE DB Destination Input" (697). The column status returned was: "The value violated the integrity constraints for the column.".

Will you please give me some idea why?