VDDK write failure

Hi,

VDDK write over SAN mode is failing with error "Failed to write to Disk One of the parameters supplied is invalid". But the same is working with NBD transport mode.

Observed following errors in hostd log:

[2011-07-14 12:08:09.720 F6421900 trivia 'VersionValidator'] ALLOWED: Host is not licensing-restricted

[2011-07-14 12:08:09.733 F6421900 info 'App'] AdapterServer caught exception: 5d8ace80

The ESX server has valid license.

Environment:

ESX: 4.1 build-260247

VDDK 1.2.1

Please suggest the cause for the error.

Thanks

Sachin