you can try one of the following methods:
Use a SCSI controller instead of a SATA or IDE controller for the emulated disk/drive. Some users reported that this worked for them.
Specify the size of the ESX-OSData partition manually by adding the parameter autoPartitionOSDataSize=8192 (or any other value in MB) after the cdromBoot runweasel command in the ESXi installer boot options.
Add a persistent storage device to the system and set autoPartition=TRUE to allow initializing it with an ESX-OSData partition