A survey in OpenForis Collect crashes

Dear OpenForis support team,

My survey crashes several times in OpenForis Collect (desktop) although I do not have issues with the same survey before. The following error appears:

java.lang.NumberFormatException: For input string: "false"
at sun.misc.FloatingDecimal.readJavaFormatString(FloatingDecimal.java:2043)
at sun.misc.FloatingDecimal.parseDouble(FloatingDecimal.java:110)
at java.lang.Double.parseDouble(Double.java:538)
at org.openforis.idm.metamodel.NumberAttributeDefinition.createValue(NumberAttributeDefinition.java:58)
at org.openforis.idm.metamodel.NumberAttributeDefinition.createValue(NumberAttributeDefinition.java:83)
at org.openforis.idm.metamodel.NumberAttributeDefinition.createValue(NumberAttributeDefinition.java:20)
at org.openforis.idm.model.expression.ExpressionEvaluator.evaluateAttributeValue(ExpressionEvaluator.java:69)
at org.openforis.idm.metamodel.AttributeDefault.evaluateExpression(AttributeDefault.java:91)
at org.openforis.idm.metamodel.AttributeDefault.evaluate(AttributeDefault.java:73)
at org.openforis.collect.model.RecordUpdater.recalculateValue(RecordUpdater.java:1134)
at org.openforis.collect.model.RecordUpdater.recalculateValues(RecordUpdater.java:485)
at org.openforis.collect.model.RecordUpdater.recalculateDependentCalculatedAttributes(RecordUpdater.java:474)
at org.openforis.collect.model.RecordUpdater.afterAttributeInsertOrUpdate(RecordUpdater.java:339)
at org.openforis.collect.model.RecordUpdater.afterAttributeUpdate(RecordUpdater.java:326)
at org.openforis.collect.model.RecordUpdater.updateAttribute(RecordUpdater.java:75)
at org.openforis.collect.command.handler.UpdateAttributeCommandHandler.executeForResult(UpdateAttributeCommandHandler.java:15)
at org.openforis.collect.command.handler.UpdateAttributeCommandHandler.executeForResult(UpdateAttributeCommandHandler.java:9)
at org.openforis.collect.command.handler.RecordCommandHandler$1$1.execute(RecordCommandHandler.java:72)
at org.openforis.concurrency.Worker.run(Worker.java:103)
at org.openforis.concurrency.Job.runTask(Job.java:95)
at org.openforis.concurrency.Job.execute(Job.java:80)
at org.openforis.concurrency.Worker.run(Worker.java:103)
at org.openforis.concurrency.SimpleJobManager$2.run(SimpleJobManager.java:120)
at org.springframework.core.task.SimpleAsyncTaskExecutor$ConcurrencyThrottlingRunnable.run(SimpleAsyncTaskExecutor.java:286)
at java.lang.Thread.run(Thread.java:748)

I hope very much you can help me to fix this problem. Cheers, Roksolana