Excel list problem
 

I create a list in Excel (office v.2001,MAC or 2004). I test the list on a PC
Excel, version 2000 or 2003. A list created in absolutely one and the same
way often works but sometimes the list appears ONLY as a basic range of
data. No further changes of the list are made on the PC and no transfer via
Email. (On any MAC and version it's 100% fine), but on a PC there is no
guarantee. Any idea? Can anybody help?
Many thanks in advance!