Simulation start time

[<allosgen@xxxxxxxxx>]

Dear Trnsys users,
I've got a series of data about solar radiation to use with solar types 
with a time step of 1 minute.
I tried to run my simulation for the first time with the data of 
January, setting the simulation start time to zero and it started 
without any problems. When I tried my second simulation with the data 
of February, instead, setting the simulation start time to 744 hr (that 
is 1st of February) this error occurred:
***** ERROR *****        TRNSYS ERROR # 203
 THE SIMULATION START TIME MUST BE AN INTEGER MULTIPLE OF THE
 SIMULATION TIMESTEP. CHECK SIMULATION STATEMENT.
I have tried many other times to run the same simulation just changing 
the simulation start time and I noticed that the problems began after a 
starting time of 312 hr.
It would be great, if someone could help me. 
kindly regards, 
Antonello Miscimarra