Correct me if I'm wrong, but it looks like you've responded to Wims as if he were reporting two separate issues with /timer: negative values and large values. If so, that is not the case.
In addition to the examples provided in the original post:
;Specifying a large interval triggers instantly:
/timertest 1 2147483647 noop
* Timer test activated
* Timer test halted
;Specifying a *larger* interval produces an error:
/timertest 1 2147483648 noop
* /timertest: invalid parameters
Since the interval gets multiplied *1000 internally (2147484 == 2147484000ms), it appears the error check is simply off by an order of 1000. No error is produced between ~2147484-2147483647, but the integer overflows and creates a negative timer which triggers instantly.
