What do you mean with the statement that you created a windows partition for SliTaz? Did you format the partition in NTFS or FAT32?
The thing with SliTaz is that it needs the partition to be formatted in the ext3 file system and it It won't work with a Windows file system like NTFS or FAT32. The easiest way is to let SliTaz install itself with the installer located @ 'start' button --> System Tools --> SliTaz Installer