Couldn't find external DTD 'futuretense_cs.dtd'

I'm using oracle webcenter sites (11.1.1.6.0 ) and I'm trying to create an attribute editor but getting below when getting..(Its picking up presentationobject.dtd from the same folder without any issues)

Also I verified the XML and it doesn't have line breaks or junk characters. 

Am I missing any configuration ?.

XML:

<?xml version="1.0" ?>

<!DOCTYPE ftcs SYSTEM "futuretense_cs.dtd">

<ftcs version="1.2">

</ftcs>

 com.openmarket.basic.interfaces.AssetException: Couldn't find external DTD 'futuretense_cs.dtd'

        at com.openmarket.gator.attributetypes.AttributeTypeManager.saveNoLocks(AttributeTypeManager.java:106)

        at com.openmarket.assetframework.complexasset.ComplexAsset.SaveNoLocks(ComplexAsset.java:1217)

        at com.openmarket.xcelerate.asset.Asset.SaveNoPubLock(Asset.java:4252)