Order Import Error

Hi There,

I am attempting to import orders from an external system into my admin site so customers who place orders over the phone can see their order status.

I am a novice at this stuff so I have no idea what this error means. Any help?

ERROR ROW: 1
UNCAUGHT ERROR: Input string was not in a correct format.: at System.Number.StringToNumber(String str, NumberStyles options, NumberBuffer& number, NumberFormatInfo info, Boolean parseDecimal) at System.Number.ParseDecimal(String value, NumberStyles options, NumberFormatInfo numfmt) at System.Convert.ToDecimal(String value, IFormatProvider provider) at AC.ACS.Shared.Helpers.DataImporter.GetColumnDataT in c:\TeamCity\agents\BuildAgent2\work\8b808e8990e4aff3\AC.ACS.Entity\Shared\Helpers\DataImporter.cs:line 1124 at AC.ACS.Shared.Helpers.DataImporter.MapColumnToOrder(Order poOrder, OrderShipping poShipment, OrderItem poOrderItem, Int32 piItemID, String psDestinationColumn, String psSourceColumnName, DataRow poSourceRow, Int32& piChangeOrderStatusIDTo) in c:\TeamCity\agents\BuildAgent2\work\8b808e8990e4aff3\AC.ACS.Entity\Shared\Helpers\DataImporter.cs:line 5124 at AC.ACS.Shared.Helpers.DataImporter.ImportOrder(DataPortSettingCol poMappingAry, CsvReader poReader, Boolean pbPostAfterValidate) in c:\TeamCity\agents\BuildAgent2\work\8b808e8990e4aff3\AC.ACS.Entity\Shared\Helpers\DataImporter.cs:line 4376