If you are using PC_PRINT_FILE on Windows then you do not need to place the file in the C:\ root directory in order to print it.
What is the name of the file that you were trying to write to?
If the filename contains a space character then you will need to enclose it within quotes when creating it but in PC_PRINT_FILE you would just leave it as is but set the filename-len parameter to the actual length of the filename. The docs for PC_PRINT_FILE specify that the name is space or NULL terminated but that is not true.
Example:
select test-file assign to '"c:\my folder\printfile.txt"'. *>double quotes enclose name surrounded by single quotes
params used in PC_PRINT_FILE
01 filename-param.
03 filename-len pic x(2) comp-5 value 26.
03 filename pic x(256)
value 'c:\my folder\printfile.txt'.