UPDATE 4-Fortis delays shareholder vote on BNP deal

* Delays vote until April 28/29

* Follows court ruling that not all shareholders can vote

* Ruling increases chance of BNP deal being rejected

* Fortis to launch an appeal against ruling

* Fortis shares weaker

(Updates with decision to delay vote)

By Antonia van de Velde

BRUSSELS, April 1 (Reuters) - Fortis NV (FOR.BR) on Wednesday postponed a shareholder vote until April 28-29 on the sale of its former banking arm to BNP Paribas SA (BNPP.PA), casting fresh doubt over whether it can complete the deal.

Fortis investors, who blocked BNP's purchase of 75 percent of Fortis Bank from the Belgian state last month, were due to vote on revised conditions for the deal at meetings in the Dutch city of Utrecht on April 8 and in Brussels on April 9.