From: "Dr. Olaf Kuhlmann" <>

Subject: Characters in error are: FWORK

Date: Mon, 18 Jun 2001 12:02:48 +0000


Dear nmusers,


I am a beginner in using NONMEM and have some problems modeling my PK PD data (ADVAN 3). I have 59 subjects, for each subject 2-3 plasma data at different time points, in total 153 records( and 10 data items).


During the run the following message arises:


"an error was found in the control statements. The characters in error are: FWORK.

36 ERROR has occurred while creating required files" (two computers tried, same result)


--> the error did not arise when I omit the first/or last 20 subjects. Is there a limitation in no. of data records? (chapter 6, page 50 of the introductory says NO).


--> second question (for my better understanding). When I omit the first (or last) 20 subjects, and everything is fine until the output file, I find in this file in the line:


No. of Data Recs in data set: --> the number 98


but some lines later:


Tot. No. of OBS Recs: --> just the number 63 (which is the correct number in my data file)


What is the reason for this difference?


Please help me...


Thanks a lot in advance




Dr.rer.nat. Olaf Kuhlmann (Dipl.-Biol.)

Martin-Luther-Universitaet Halle-Wittenberg

Medizinische Fakultaet

Institut fuer Pharmakologie und Toxikologie

Sektion Pharmakokinetik

Magdeburger Str. 4

06097 Halle/Germany


Tel.: 0345-5574091

FAX : 0345-5571835