strange error on ssis package excution

I was totally blank when i got the error saying OLE DB provider 'STREAM' for linked server '(null)' returned invalid data for column '[!BulkInsert].sak_beregnetrente

I was doing a bulk data transfer from faircom ctree server to sql server 2005 using ssis. the faircom db is a large database and very difficult to figure out where the error was.
I then tried to check the null values of the data column "sak_beregnetrente". but it contained more than 20 million records. then i used a ssis derived column to check the null using the expression

[sak_beregnetrente] == NULL(DT_R8) ? 0 : [sak_beregnetrente]

this will check the NAN values for the column data because the data type is float.

eahhhhh, this solved my problem