There are differing types of timers on sale. Some timers actually switch a pair of contacts to switch on the device being timed. This means they can switch any load up to their contact rating. Other types of timers use an electronic switch to control the load. Some of these type of timers do not like to switch a small load (such as a low power lamp) and this is probably why a general statement has been made about timers and low power bulbs
Thank you for your reply- I can understand why it shouldn't be used with a dimmer switch but it definitely says on the packing that the bulb is not to be used with a timer.