Am Facing an VisualForce  Error

" common.formula.FormulaParseException: Syntax error. Found 'if'  " 

When I click the New CutomObject Button am getting this Error..... it is due to the value="{!if(ActiveTab != null, ActiveTab, 'tab1')}"  attribute of  my  <apex:TabPanel>

check 

<apex:tabPanel switchType="client" id="tabpanel" value="{!if(ActiveTab != null, ActiveTab, 'tab1')}" >

Which is not allowing to redirect to New record page , when is use a Fomula in Action attribute 

<apex:commandButton value="New PortofOrigin" action="{!URLFOR($Action.Port_of_Origin__c.New)}"> OR Even directly with URL link 

<apex:commandButton value="New PortofOrigin" action="https://cs5.salesforce.com/a0R/e?retURL=%2Fa0R%2Fo" >

My Visualforce Page:

<apex:page showHeader="false" id="thePage" controller="extensionController1">
    <script>
        function setCookie(c_name,value)
        {
            var exdate=new Date();
            exdate.setDate(exdate.getDate() + 99);
            var c_value=(escape(value) + : "; expires="+exdate.toUTCString());
            document.cookie=c_name + "=" + c_value;
        }
    </script>
<apex:form id="form">
<apex:actionFunction name="setTab" onComplete="return false;" rerender="tabpanel">
<apex:param name="activeTab" assignTo="{!ActiveTab}" value="" />
</apex:actionFunction>

<apex:tabPanel switchType="client" id="tabpanel" value="{!if(ActiveTab != null, ActiveTab, 'tab1')}" tabClass="activeTab" inactiveTabClass="inactiveTab" >
<!-- TAB ONE STARTS -->
<apex:tab title="tab1" label="tab1" id="object1" name="tab1" ontabenter="setCookie('apex__counter','tab1');" switchType="client">
<apex:message title="Error"/>

<apex:pageBlock title="tab1" mode="edit" tabStyle="Sourcing__tab">
  <!-- NEW BUTTON WHICH WHEN CLIKCED FOR -->

        <apex:pageBlockButtons location="top" style="padding-left:70px;">
         <apex:commandButton value="New CustomObject1" action="{!URLFOR($Action.CustomObject1__c.New)}" style="font-size:12px;font-weight:bold;width:120px;"/>
        </apex:pageBlockButtons> 
       
</apex:pageblock>
</apex:tab>
<!-- TAB TWO STARTS -->

<apex:tab title="tab2" label="tab2" id="object2" name="tab2" ontabenter="setCookie('apex__counter','tab2');" switchType="client">
<apex:message title="Error"/>

<apex:pageBlock title="tab1" mode="edit" tabStyle="Sourcing__tab">
  <!-- NEW BUTTON WHICH WHEN CLIKCED FOR -->

        <apex:pageBlockButtons location="top" style="padding-left:70px;">
         <apex:commandButton value="New CustomObject2" action="{!URLFOR($Action.CustomObject2__c.New)}" style="font-size:12px;font-weight:bold;width:120px;"/>
        </apex:pageBlockButtons> 
       
</apex:pageblock>
</apex:tab>
</apex:tabpanel>
</apex:form>
</apex:page>

 The Controller is:

public with sharing class extensionController1 {
    
    public string ActiveTab  { get; set; }

    public extensionController1()
    {
        Cookie counter = ApexPages.currentPage().getCookies().get('counter');

        // If this is the first time the user is accessing the page,   
        // create a new cookie with name 'counter', an initial value of '1',   
        // path 'null', maxAge '-1', and isSecure 'false'.   
            if (counter ==null) {
                counter = new Cookie('counter','tab1',null,999,false);
                // Set the new cookie for the page  
                ApexPages.currentPage().setCookies(new Cookie[]{counter});
            } else {
        // If this isn't the first time the user is accessing the page  
        // create a new cookie, incrementing the value of the original count by 1  
            
                ActiveTab = String.valueOf(counter.getValue());
            }
            system.debug('@@ActiveTab: ' + ActiveTab);
    }
}

 Please provide a Solution to this,Such that I can use the last selected tab Functionality and create new records from the tabpanel.

-Thank you