pig ERROR 1200: null when using fs commands - hadoop

Question

while running pig in mapreduce mode im occuring really strange error.
The pigscript.pig contains....
x= load 'hdfs://file.avro' USING AvroStorage();
some transofrmations...
fs mv src/file dest/file;
up to this point all works fine, but script continues as
y = load 'hdfs://file2.avro' USING AvroStorage();
While executed previous command i got error bellow. I double check and the file2.avro is there ... stored in the HDFS.
When I quit pig and re-run the code from the line
y = load 'hdfs://file2.avro' USING AvroStorage();
all works fine.
Any idea?
Pig Stack Trace
---------------
ERROR 1200: null
Failed to parse: null
at org.apache.pig.parser.QueryParserDriver.parse(QueryParserDriver.java:201)
at org.apache.pig.PigServer$Graph.validateQuery(PigServer.java:1707)
at org.apache.pig.PigServer$Graph.registerQuery(PigServer.java:1680)
at org.apache.pig.PigServer.registerQuery(PigServer.java:623)
at org.apache.pig.tools.grunt.GruntParser.processPig(GruntParser.java:1063)
at org.apache.pig.tools.pigscript.parser.PigScriptParser.parse(PigScriptParser.java:501)
at org.apache.pig.tools.grunt.GruntParser.parseStopOnError(GruntParser.java:230)
at org.apache.pig.tools.grunt.GruntParser.parseStopOnError(GruntParser.java:205)
at org.apache.pig.tools.grunt.Grunt.run(Grunt.java:66)
at org.apache.pig.Main.run(Main.java:558)
at org.apache.pig.Main.main(Main.java:170)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.apache.hadoop.util.RunJar.run(RunJar.java:221)
at org.apache.hadoop.util.RunJar.main(RunJar.java:136)
Caused by: java.lang.NullPointerException
at org.apache.pig.builtin.AvroStorage.getAvroSchema(AvroStorage.java:298)
at org.apache.pig.builtin.AvroStorage.getAvroSchema(AvroStorage.java:282)
at org.apache.pig.builtin.AvroStorage.getSchema(AvroStorage.java:256)
at org.apache.pig.newplan.logical.relational.LOLoad.getSchemaFromMetaData(LOLoad.java:175)
at org.apache.pig.newplan.logical.relational.LOLoad.<init>(LOLoad.java:89)
at org.apache.pig.parser.LogicalPlanBuilder.buildLoadOp(LogicalPlanBuilder.java:901)
at org.apache.pig.parser.LogicalPlanGenerator.load_clause(LogicalPlanGenerator.java:3568)
at org.apache.pig.parser.LogicalPlanGenerator.op_clause(LogicalPlanGenerator.java:1625)
at org.apache.pig.parser.LogicalPlanGenerator.general_statement(LogicalPlanGenerator.java:1102)
at org.apache.pig.parser.LogicalPlanGenerator.statement(LogicalPlanGenerator.java:560)
at org.apache.pig.parser.LogicalPlanGenerator.query(LogicalPlanGenerator.java:421)
at org.apache.pig.parser.QueryParserDriver.parse(QueryParserDriver.java:191)
... 16 more
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