XSL not found, migratign from WAS6 to 7

[Tejas Anand Gokhale]

I am migrating a simple web app from websphere 6 to 7, with a front controller servlet which renders the output through an xsl.
I am using org.apache.xalan.processor.TransformerFactoryImpl to tranform the XSL.
I have configured path of working directory for the server where the XSLs exist. But I am getting error saying XSL not found during tranformation at line:

tFactory.newTransformer(new StreamSource( new File(xslFileName)));

this was not the case for websphere 6. What is the problem. Help!!!