|If you installed NT 4.0, the maximum size of the primary partition DURING SETUP is 4 GB.|
You can later add additional partitions or enlarge the primary partition AFTER setup using special software. This equals maximum 4095 MB on the blue DOS-based setup screen. If you left it at 8057 MB (default), that is your problem. Restart NT Setup and overwrite the default value with 4095 MB.
Boot Partition Created During Setup Limited to 4 Gigabytes: