error using textscan with csv files

I have been given a code to process some data in a csv file. When I run this I get the error below. Can anybody help?

fid = fopen('time.csv');
out = textscan(fid,'%s %f %f %s','delimiter',',','headerlines',1);
fclose(fid);

Error using textscan
Invalid file identifier. Use fopen to generate a valid file identifier.

Answer 1

[Walter Roberson]

The fopen failed. The file does not exist in the matlab path, or you do not have permission. if you used the two-output form of fopen you would get a message about why it failed.