Assignment of Tax procedure to Country code is Mandatory. This can be done in OBBG. You must assign the tax procedure even though your country does not have taxes.
1) Copy the Tax Procedure (Any) and Rename it as per your requirement. You can use existing one also say TAXSG (There is no harm if you use existing tax procedure as you are not going to use the Taxes) But, keeping future in mind, it is better you copy any tax procedure and make the changes as per your requirement. I.e. Remove the condition types and keep one or two condition type (could be any) for the purpose of maintaining condition records with zero percentage.
2) Assign Tax procedure to Country Code AE (In your case)
3) Create One Input and One Out put tax codes
4) Assign Tax codes to Company codes
5) Maintain condition record in FV11 for the condition type that is assigned to your tax procedure with Zero percentage and proceed.
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