>>>It is valid.
>>>Even in Excel itself you can't use more than 31 chars to name a sheet.
>>
>>Where is the limitation come from and how should I code around it?
>>
>>I don't see it here
>>http://office.microsoft.com/en-us/excel/HP051992911033.aspx
>
>Have no idea :-)
>Maybe the Excel Team sit once on their backs and decided to limit the Sheet name to 31 chars, why 31 and not 32 or 64 is above me (but maybe there is a reason) :-)

In the meantime I re-coded and testing right now. I wish there would not be such limittion.