Creating links from Indesign to PDF

I have created a pdf document with hot links from Indesign software. When I open the pdf with acrobat reader the links are working fine, when I open it in a browser the links are also working. But the links don't work in the Acrobat 6.0 software.

Is there a way around my problem or is this the way it should work anyway?

Many thanks for your help.
Silly question, but have you saved the PDF as the lowest/earliest possible version (in the compatibility dialogue box), with the include hyperlinks box ticked when saving?