ADDENDUM FOR EMPLOYEES IN THE NETHERLANDS

TAX INFORMATION

         This addendum does not discuss all of the tax consequences that may be
relevant to you in your particular circumstances, but is merely intended to
alert you to some of the tax information you may want to consider in making your
decision.

         You may have already paid tax on the portion of your eligible options
that has vested. In addition, any tender of your eligible options for
cancellation may be viewed as an exercise which could trigger additional tax
liability if the tender occurs within three years of your grant date. The
precise amount and method of calculation of such tax liability is uncertain. It
is our understanding that the amount of any taxes paid or payable on account of
the eligible options would not be recoverable nor credited against any future
tax you will be required to pay in connection with the new options granted to
you pursuant to the terms of the offer.

         If you choose to tender your eligible options, any grant of new options
will be conditioned on your execution of an agreement to limit your method of
exercise to a mandatory cashless exercise (same day sale). As a consequence, the
taxable event will be deferred from vesting to the exercise date.

         Please note that tax laws change frequently and vary with your
individual circumstances. Please consult a tax advisor to determine the tax
considerations and tax consequences relevant to your participation in the offer.

CONDITION TO ACCEPTANCE

         The acceptance of your tender of eligible options is subject to
compliance with local labor law.