Series data points do not support values of type System.Byte[]

Question

Hi there, I hope your help.

I posted three topics in this forum and I don't have be answered...

I try this query in asp net:

 String strQuery = "SELECT " +
                           "CASE WHEN tot_current_year = 0 THEN '' " +
                           "ELSE tot_current_year " +
                           "END AS tot_current_year " +
                           "FROM myTable ";

And receive this error, can you help me?
thanks

ERROR:
Series data points do not support values of type System.Byte[] only values of these types can be used: Double, Decimal, Single, int, long, uint, ulong, String, DateTime, short, ushort.