Hmm... A couple possibilities
1) Try disabling your anti-virus while you write the image (assuming, of course, you have anti-virus

)
2) Is your SD card large enough? WinDiskImg32 shouldn't even try to write it if the SD card is too small... but maybe yours is?
3) Are you trying to write the .zip file or have you extracted it and are trying to write the .img file?
4) Try doing a complete format of the disk, start with a quick format using FAT32 as the partition size, and be sure to use the entire disk to create a single partition, if that doesn't work try a slow format
5) Try running windiskimg32 as an administrator (right click the program and say "Run as Administrator") even if you're already an admin, you have to do this to use those admin privileges