Sql Syntax

Hello, I cannot get the syntax of a sql stored procedure correct.  Here are the errors I get:

Msg 156, Level 15, State 1, Procedure sp_CheckRefferingID, Line 9
Incorrect syntax near the keyword 'Insert'.
Msg 1046, Level 15, State 1, Procedure sp_CheckRefferingID, Line 10
Subqueries are not allowed in this context. Only scalar expressions are allowed.
Msg 156, Level 15, State 1, Procedure sp_CheckRefferingID, Line 15
Incorrect syntax near the keyword 'Else'.
Msg 156, Level 15, State 1, Procedure sp_CheckRefferingID, Line 18
Incorrect syntax near the keyword 'Else'.
Msg 156, Level 15, State 1, Procedure sp_CheckRefferingID, Line 21
Incorrect syntax near the keyword 'Insert'.
Msg 156, Level 15, State 1, Procedure sp_CheckRefferingID, Line 25
Incorrect syntax near the keyword 'Else'.
Msg 102, Level 15, State 1, Procedure sp_CheckRefferingID, Line 26
Incorrect syntax near ')'.

Thanks!

create procedure sp_CheckRefferingID
	@RefferingID int,
	@RefferingDomain VarChar(100),
	@ClientIP VarChar(15)
As
	If Exists(Select * From UserDomains Where UserID = @RefferingID and DomainName = @RefferingDomain)
		If Not Exists(Select * From InboundTraffic Where IP = @ClientIP and VisitStart > DateAdd(Minute, -60, GetDate())
			--Insert New Visitor
			Insert Into InboundTraffic(DomainID, VisitStart, IP)
			Values ((Select DomainID From UserDomains Where DomainName = @RefferingDomain), GetDate(), @ClientIP)
			--Update User Credit Balance
			Update Users Set PixelCredits = PixelCredits + 1 Where UserID = RefferingID
			--Select QueryData
			Select 1, (Select Top 1 VisitorID From InboundTraffic Where IP = @ClientIP and VisitStart > DateAdd(Minute, -60, GetDate())
		Else
			--Visiotor Already Registered
			Select 2, (Select Top 1 VisitorID From InboundTraffic Where IP = @ClientIP and VisitStart > DateAdd(Minute, -60, GetDate())
	Else
		If Not Exists(Select * From InboundTraffic Where IP = @ClientIP and VisitStart > DateAdd(Minute, -60, GetDate())
			--Insert New Visitor
			Insert Into InboundTraffic(DomainID, VisitStart, IP)
			Values (null, GetDate(), @ClientIP)
			--Select QueryData
			Select 3, (Select Top 1 VisitorID From InboundTraffic Where IP = @ClientIP and VisitStart > DateAdd(Minute, -60, GetDate())
		Else
			Select 4, (Select Top 1 VisitorID From InboundTraffic Where IP = @ClientIP and VisitStart > DateAdd(Minute, -60, GetDate())

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