abaqus imperfection command don't function

[975386420]

I'm performing one analysis in ABAQUS 6.7.1,
I'm introducing a deformation using the command *IMPERFECTION:

*imperfection, file=RootJointExt, step=1, nset=ALL_NODES
1, 1.0

I receive this error when abaqus starts reading the
RootJointExt.fil:

***ERROR: AN ERROR OCCURED WHILE OPENING/READING THE FILE /data2/users/adangeli/run65_FL_2_1/RootJointExt.fil. MAKE SURE YOU SPECIFIED THE CORRECT FILENAME WITHOUT THE EXTENSION. FILENAMES ARE CASE SENSITIVE ON CASE SENSITIVE OPERATING SYSTEMS.

the problem is that one time it functions without problem, I tried to reproduce the simulation but it didn't work. what can I do?

 

[achilles03]

Is your .fil file in the same directory as the input file? Or do you have the .fil file open with another program?