I found that if a single cell includes greater than 1024 chars, using
property Range.FormulaR1C1to read content from the cell must cause an
exception, say

System.Runtime.InteropServices.COMException (0x800A03EC): Exception
from HRESULT
: 0x800A03EC
at System.RuntimeType.ForwardCallToInvokeMember(Strin g memberName,
BindingFla
gs flags, Object target, Int32[] aWrapperTypes, MessageData& msgData)
at Microsoft.Office.Interop.Excel.Range.get_FormulaR1 C1()

However, same code, just after keeping chars less than 1024 in a single
cell, everything is ok.

Is it a Microsoft.Office.Interop.Excel implemenation error?
I used MS Excel 11.0 Object Library.

Thx in advance!