[MSNoise] plotting error

Dear All, The whole cron.sh was humming a long nicely on our MSNoise network, until I changed from stacking 1,2 and 5 days (initially) to 1,2,3,4,5,30 days. Now, all steps seem to run UNTIL the plot command. Here is the error (after putting a print statement on the cause of the problem, df): (I run as sudo, because root is running the cron.sh overnight:) [kasper@localhost MSNoise-master]$ sudo python s07plot_dtt.py loading 1 days Empty DataFrame Columns: [A, EA, EM, EM0, M, M0, Pairs] Index: [] Empty DataFrame Columns: [A, EA, EM, EM0, M, M0, Pairs] Index: [] Traceback (most recent call last): File "s07plot_dtt.py", line 102, in <module> alldf = alldf.append(df) File "/usr/lib64/python2.7/site-packages/pandas/core/frame.py", line 4266, in append verify_integrity=verify_integrity) File "/usr/lib64/python2.7/site-packages/pandas/tools/merge.py", line 883, in concat return op.get_result() File "/usr/lib64/python2.7/site-packages/pandas/tools/merge.py", line 964, in get_result new_data = self._get_concatenated_data() File "/usr/lib64/python2.7/site-packages/pandas/tools/merge.py", line 1007, in _get_concatenated_data new_data[item] = self._concat_single_item(rdata, item) File "/usr/lib64/python2.7/site-packages/pandas/tools/merge.py", line 1094, in _concat_single_item return com._concat_compat(to_concat, axis=self.axis - 1) File "/usr/lib64/python2.7/site-packages/pandas/core/common.py", line 1191, in _concat_compat axis=axis) ValueError: need at least one array to concatenate