The error "Error accessing product object method" was encountered when running some lotusscript using a release 4 client.

The problem was that I had used the method TimeDifferencedouble instead of TimeDifference with a notesdatetime item.

Long is -2,147,483,648 to 2,147,483,647 seconds

which gives a range of 68 years!

The range of Double values is -1.7976931348623158E+308 to 1.7976931348623158E+308, inclusive.
On UNIX platforms, the range is -1.7976931348623156E+308 to 1.797693134862315E+308, inclusive.

The smallest non-zero Double value (disregarding sign) is 2.2250738585072014E-308.

Which gives a range of over 2300 years I think, well big enough for most things I reckon.