iraf.net

Hello,
I'm trying to automatically perform some long-slit spectral reduction in python using Iraf.
After performing a series of previous operations on my files, my problem comes with the command fitcoords, that fails saying it is not able to get the database file.
I execute the command in the same folder where I place the .fits file containing the spectral features to recognize (arc2.fits), while I place the database file in a subdirectory called 'database', giving this kind of input:

iraf.fitcoords('arc2', inter='no', functio="legendre",xorder='5', yorder='8')

getting this kind of output:

Longslit coordinate fit name is arc2.
Longslit database is ..
Features from images:
arc2
Warning: Cannot open file (./idarc2)

The interesting point is that the same command works fine if I perform it in a brand new python session. The latter circumstance makes me guess there is some kind of conflict with some other iraf command that I used before that point. In the next steps of data reduction, I use iraf commands like 'imcombine', 'imarith', 'imcopy', 'response', 'reidentify'.

Any suggestion is welcome.

Thank you in advance.