Are there any laws in Delaware which require and employer to accrue vacation while on Workers Compensation and/or can vacation time be reduced because I was out of work receiving Workers Comp benefits.

No, only that you should really treat everyone the same way. If your policy provides that you don't accrue vacation for employees on an unpaid leave, then you treat your employee on leave because of WC equally. Also, is FMLA running concurrently with this WC absence?

;) Can an employee be protected by FMLA while out due to a w/c injury?

They not only can, but if the employer, the employee and the condition all qualify under FMLA, they must.