SimEvents, Invalid entity intergeneration time (causes Block)

[Look at my SimEvent model here: https://www.dropbox.com/sh/g99apgo8l21moam/Hkn605vuuL]

I am trying to build a rather simple model with 4 servers each with 15 minutes service times. And I have following custom distribution that I want to use for the entities arriving into the sytem: Arrivals per hour (for 24 hours):

2, 0, 1, 0, 0, 3, 6, 11, 9, 4, 15, 17, 10, 8, 15, 21, 26, 18, 14, 23, 17, 4, 2, 0,

This data has the mean of 9.42 and the stdev 8.12, I want to see how many servers I need to get 0 waiting time and look at the utilization %. I was planning on using a normal distribution to fit this data with the given mean and stdev.. (sorry for long intro to question)

But, I always receive this error when running the simulation with normal distribution ?

"Invalid entity intergeneration time of -0.257201 in 'JOB/Time-Based Entity Generator' block at time 45.1585. Intergeneration time must be >= 0."

I need help with this error and what I could do to avoid this, Help is very much appreciated!

[Kjartan S]

some one please ?