require bug?

Hi all.
I was having this strange problem with my program.
An error happened in the code: require 'corr'

Error: error loading module 'corr' from file 
'app/geresim/prerock/lua/corr': cannot read 
app/geresim/prerock/lua/corr: Is a directory

This error does not happen in Windows but is happening in my Linux machine.
The problem is, the 'app/geresim/prerock/lua' directory contains both a 
'corr' directory and a 'corr.lua' file.
In loadlib.c, 'require' uses this 'readable' function to search 
package.path for existent lua files:

332 static int readable (const char *filename) {
333   FILE *f = fopen(filename, "r");  /* try to open file */
334   if (f == NULL) return 0;  /* open failed */
335   fclose(f);
336   return 1;
337 }

The problem is, apparently fopen succeeds when trying to open a 
directory but later on, when the file is actually fread from, this error 
happens.
I changed 'readable' so that it will fail if reading from the file fails:

332 static int readable (const char *filename) {
333   int ret = 1;
334   FILE *f = fopen(filename, "r");  /* try to open file */
335   if (f == NULL) return 0;  /* open failed */