Renaming file in C++ failing

[straygrey]

I have a C++ program running on Windows XP compiled with Visual C++ 6.0 containing the following code

if (remove(NewName) != 0)
{
errmsg = strerror(errno);
printf("Removal Error: %s\n", errmsg);
}


if (rename(FileName,NewName) != 0)
{
errmsg = strerror(errno);
printf("Rename Error: %s\n", errmsg);
}

and this fails, offering to send a message to Microsoft about the error of my ways.
The file I want to rename(FileName) does exist and the file I want to rename it to(NewName) does not and none of my error messages appear.
Please make suggestions on how I should fix this.