Resolve "unable to open output file" error while building in Configuration Desk

When attempting to build a model in ConfigurationDesk, the build fails and the following error message is displayed in ConfigurationDesk's log:

 ==== Starting build process ====================================================

 Model code generation started for model(s): '**model name**'...

 Generating model code for model '**model name**' ...

 Could not generate model code for model '**model name**'. See MATLAB Command Window for details.

 Could not generate model code for the following model(s): '**model name**'.

 ==== Build process aborted =====================================================

The MATLAB command window shows:

 Error: File: C:\Program Files (x86)\dSPACE RCPHIL 7.4\MATLAB\DSRTSU\TLC\rti_modeltrc_blk.tlc Line: 369 Column: 29
 Unable to open output file .\.\**model name**_dsrt\\**model name**_usr_hdr_on.trc.part

 Main program:

 ==> [00] C:\Program Files (x86)\dSPACE RCPHIL 7.4\MATLAB\DSRTSU\TLC\rti_modeltrc_blk.tlc:FcnUserVariablesGroupGen(369)

     [01] C:\Program Files (x86)\dSPACE RCPHIL 7.4\MATLAB\DSRTSU\TLC\rti_modeltrc_blk.tlc:<NONE>(3394)

The error repeats several times with a different value in the parentheses after FcnUserVariablesGroupGen.

I'm not sure how to resolve this issue, but I suspect that something I've selected in Simulink is causing the error. I'm using the dsrt.tlc target file and the model is fixed step, ode3.