it's a bug in the 5.4.0 script - it's been resolved for 5.5.0 . It's not something to worry about (it's only a constraint that will be added in 5.5.0 anyway - and it was ran in a go block so it's failure doesn't affect any of the rest of the script). If you like you can rerun it anyway - log in as host and go to host->sql paste this script and ensure the checkbox is checked.
/* Cleanup code Add Foreign Key to PortalLocalization Table for previous failed 5.4.0 versions */
/***********************************************************************************************/
IF NOT EXISTS (SELECT * FROM dbo.sysobjects WHERE id = object_id(N'FK_{objectQualifier}PortalLocalization_{objectQualifier}Portals') AND OBJECTPROPERTY(id, N'IsForeignKey') = 1)
BEGIN
/* Delete unused entries in PortalLocalization */
DELETE FROM {databaseOwner}{objectQualifier}PortalLocalization WHERE portalID not In (SELECT PortalID from {databaseOwner}{objectQualifier}Portals)
/* add key and cascade delete rule */
ALTER TABLE {databaseOwner}{objectQualifier}PortalLocalization
ADD CONSTRAINT FK_{objectQualifier}PortalLocalization_{objectQualifier}Portals
FOREIGN KEY ( PortalID ) REFERENCES {databaseOwner}{objectQualifier}Portals ( PortalID ) ON DELETE CASCADE
END
GO