Well, the problem is, as usually, in not reading the "bible".

Disabling interrupts does not mean it won't set the appropriate flags if the interrupt-triggering event occurs (e.g. if the timer rolls over). If you don't like the idea that the interrupt occurs immediately after reenabling it, you can:
- clear the appropriate flag indicating the the triggering event occured (here, clr tf0) (but then if the event occurs immediately after clearing the flag, the interrupt will be invoked anyway - note that you never set th0:tl0 so this might very well happen)
- prevent the triggering event to occur (here, stop the timer when disabling interrupt)
[Edit]: whoops sorry I somehow got the idea your problem is with the timer interrupt. Then only the first method works - see Erik's post.

Jan Waclawek

PS. Next time, please enclose your program within <pre> and </pre> tags to keep its formatting.