Why every time a Macro fails, next time i try to execute it again the following message appears?:

java.lang.NullPointerException: Null Pointer in Method Invocation
at bsh.Name.invokeMethod(Name.java:844)
at bsh.BSHMethodInvocation.eval(BSHMethodInvocation.java:75)
at bsh.BSHPrimaryExpression.eval(BSHPrimaryExpression.java:102)
at bsh.BSHPrimaryExpression.eval(BSHPrimaryExpression.java:47)
at bsh.BSHCastExpression.eval(BSHCastExpression.java:60)
at bsh.BSHReturnStatement.eval(BSHReturnStatement.java:48)
at bsh.BSHBlock.evalBlock(BSHBlock.java:130)
at bsh.BSHBlock.eval(BSHBlock.java:80)
at bsh.BshMethod.invokeImpl(BshMethod.java:362)
at bsh.BshMethod.invoke(BshMethod.java:258)
at bsh.BshMethod.invoke(BshMethod.java:186)
at bsh.Name.invokeLocalMethod(Name.java:917)
at bsh.Name.invokeMethod(Name.java:804)
at bsh.BSHMethodInvocation.eval(BSHMethodInvocation.java:75)
at bsh.BSHPrimaryExpression.eval(BSHPrimaryExpression.java:102)
at bsh.BSHPrimaryExpression.eval(BSHPrimaryExpression.java:47)
at bsh.BSHVariableDeclarator.eval(BSHVariableDeclarator.java:86)
at bsh.BSHTypedVariableDeclaration.eval(BSHTypedVariableDeclaration.java:84)
at bsh.BSHBlock.evalBlock(BSHBlock.java:130)
at bsh.BSHBlock.eval(BSHBlock.java:80)
at bsh.BshMethod.invokeImpl(BshMethod.java:362)
at bsh.BshMethod.invoke(BshMethod.java:258)
at bsh.BshMethod.invoke(BshMethod.java:186)
at bsh.Name.invokeLocalMethod(Name.java:917)
at bsh.Name.invokeMethod(Name.java:804)
at bsh.BSHMethodInvocation.eval(BSHMethodInvocation.java:75)
at bsh.BSHPrimaryExpression.eval(BSHPrimaryExpression.java:102)
at bsh.BSHPrimaryExpression.eval(BSHPrimaryExpression.java:47)
at bsh.BSHBlock.evalBlock(BSHBlock.java:130)
at bsh.BSHBlock.eval(BSHBlock.java:80)
at bsh.BshMethod.invokeImpl(BshMethod.java:362)
at bsh.BshMethod.invoke(BshMethod.java:258)
at bsh.BshMethod.invoke(BshMethod.java:186)
at bsh.Name.invokeLocalMethod(Name.java:917)
at bsh.Name.invokeMethod(Name.java:804)
at bsh.BSHMethodInvocation.eval(BSHMethodInvocation.java:75)
at bsh.BSHPrimaryExpression.eval(BSHPrimaryExpression.java:102)
at bsh.BSHPrimaryExpression.eval(BSHPrimaryExpression.java:47)
at bsh.BSHVariableDeclarator.eval(BSHVariableDeclarator.java:86)
at bsh.BSHTypedVariableDeclaration.eval(BSHTypedVariableDeclaration.java:84)
at bsh.Interpreter.eval(Interpreter.java:645)
at org.gjt.sp.jedit.BeanShell._runScript(BeanShell.java:341)
at org.gjt.sp.jedit.BeanShell._runScript(BeanShell.java:286)
at org.gjt.sp.jedit.BeanShell.runScript(BeanShell.java:212)
at org.gjt.sp.jedit.Macros$BeanShellHandler.runMacro(Macros.java:1013)
at org.gjt.sp.jedit.Macros$Macro.invoke(Macros.java:436)

Bug?

Thanks