0PROGRAM TERMINATED BY OBJ
ERROR IN CELS WITH INDIVIDUAL 1 ID= 1.00E+00
SUM OF SQUARED WEIGHTED INDIVIDUAL RESIDUALS IS INFINITE
MESSAGE ISSUED FROM ESTIMATION STEP
AT INITIAL OBJ. FUNCTION EVALUATION
This message means that you likely have a predicted value of 0 at some point (maybe a predose sample).
Usually this error points out to zero variance of the residual error. In a case of a proportional error model. If prediction is zero (or close to zero) at some point, you may get this error message. You should try to estimate the additive part of the error model.
If the first observation is before ALAG1 time, you will get zero prediction