Excel 2007 : option to Enable Macro not available

Hello

I was using Excel 2003 uptill now. And nw recently started using Excel 2007. I have file (developed myself) in Excel 2003 format with UserForms, macros etc. I saved this file in Excel 2007 macro-enabled files ( file extention is xlsm). When I open this file 'Security Warning ' appears as 'Macros have been disabled'. There is one button beside ;'Option'. If I clickd it I ecpect that option button wiht 'Enable Macro' shoud be there. But it is not there. Below mentioned messege appears
'To run these macros, remove the encryption or permission restriction on file'
What this mean? How to enable macros in this case?

Plese help.