Error: Uncaught exception 'Exception' with message 'ABORTED:

By importing a big set of csv files, I got the following error in shell for every value in the same row:

Fatal error: Uncaught exception ‘Exception’ with message ‘ABORTED: Call to undefined module method. Missing function on module? method=add_feed’ in /var/www/html/emon/Modules/process/process_model.php:51
Stack trace:
0 /var/www/html/emon/Modules/process/process_model.php(88): Process->__call(‘add_feed’, Array)
1 /var/www/html/emon/Modules/process/process_model.php(88): Process->add_feed(‘18’, 1465297020, NULL, Array)
2 /var/www/html/emon/Modules/feed/engine/VirtualFeed.php(84): Process->input(1465297020, NULL, ‘29:18,29:26,29:…’, Array)
3 /var/www/html/emon/Modules/feed/feed_model.php(401): VirtualFeed->lastvalue(179)
4 /var/www/html/emon/Modules/process/process_processlist.php(613): Feed->get_timevalue(‘179’)
5 [internal function]: Process_ProcessList->add_feed(‘179’, 1465296061, 134.32, Array, Object(Process))
6 /var/www/html/emon/Modules/process/process_model.php(48): call_user_func_array(Array, Array)
7 /var/www/html/emon/Modules/process/process_model.php(88): Process->__call(‘add_feed’, Array)
8 /var/www/h in /var/www/html/emon/Modules/process/process_model.php on line 51

It seems to be related to the name of the used key, e.g. “p” in my import script. If I change the key to e.g. “pw”, the error does not occur.
Can anyone help me with this issue, because renaming the key will change the imput and result in a new feed.