org.drools.eclipse.builder.DroolsBuilder assumes all XLS files are decision tables and attempts to compile them, leading to the error "No RuleTable cells in spreadsheet."

When using *.XLS (templates in this case)in drools 5.2.0 final and Eclipse 3.7.1 indigo , they are being considered as decision tables and hence leading to the error "No RuleTable cells in spreadsheet."