intervalmatch (matchfield) (loadstatement | selectstatement )
matchfield is the field containing the discrete numeric values to be linked to intervals.
loadstatement or selectstatement must result in a two-column table, where the first field contains the lower limit of each interval and the second field contains the upper limit of each interval. The intervals are always closed, i.e. the end points are included in the interval. Non-numeric limits render the interval to be disregarded (undefined) while NULL limits extend the interval indefinitely (unlimited).
So I think you should write your intervalmatch load statement like:
IntervalMatch (value) load begin, end resident myInterval;
(You might consider changing your intervals to non-overlapping, too)