FATAL ERROR: Setting parameter constraints from script failed!

From: Do Nhu Trang (dntrang_at_gmail.com)
Date: Thu Jan 08 2009 - 09:57:28 CST

Dear all,

I would like to perform a simulation with restraints released gradually. I
want to control several phases in one configuration file. The procedure I
have done is the following:

1. turn on the constraints
2. specify the reference pdb file together with force constant
3. run for a number of timesteps
4. turn off the constraints
5. turn on again with another reference pdb file and force constant
6. run for another number of timesteps
...
The detail script of this part is attached below. After running for the
first number of steps (20000 in this case), NAMD stops running and reports
this following error:
"TCL: Setting parameter constraints to off
FATAL ERROR: Setting parameter constraints from script failed!"

I found the similar problem reported by Marc vander Kamp a long time ago
http://www-s.ks.uiuc.edu/Research/namd/mailing_list/namd-l/1095.html
but there is still no reply to this message. I would like to ask Marc if he
could already solve this problem, and I also need help from all NAMD users.

Many thanks.
Trang.

#####################

constraints on
consref K_18_restrained_5.pdb
conskfile K_18_restrained_5.pdb
conskcol B
run 20000;
constraints off;

constraints on;
consref K_18_restrained_3.pdb;
conskfile K_18_restrained_3.pdb;
conskcol B;
run 5000;
..........

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