Is that the previous declaration, or is that the line with the warning? 'Cause there are going to be two different lines listed here, obviously; the first line where the error is, and then a different line where the previous declaration was.
Anyway, the two don't match (the use and the declaration). So fix that.
Edit: To be more specific, your file must look like the following:
Code:
void function(int, float, int, int, float);
int main(void) {
/* things happen here */
}
void function(int a, float b, int c, int d, float e) {
/* the actual function is here */
}