diff --git a/pam_yubico.c b/pam_yubico.c
index 4a23922..04ed5f0 100644
--- a/pam_yubico.c
+++ b/pam_yubico.c
@@ -761,7 +761,7 @@ parse_cfg (int flags, int argc, const char **argv, struct cfg *cfg)
             }
           else
             {
-              FILE *file = fopen(argv[1] + 11, "a+");
+              FILE *file = fopen(argv[i] + 11, "a+");
               if(file)
                 {
                   cfg->debug_file = file;