After deleting the file, a new file was created. I can open this this file in the backend now. So that seems okay.
When I looked in the big file, after I downloaded it with FTP, I saw this:
******************************************************************************************************************************************************
******************** 15 mei 2013 20:25 ********************
HikaShop opgevraagd op 15 mei 2013 20:25
---- Details ----
Orders checked
******************************************************************************************************************************************************
******************** 18 mei 2013 11:33 ********************
HikaShop opgevraagd op 18 mei 2013 11:33
---- Details ----
Orders checked
Wisselkoersen succesvol bijgewerkt
******************************************************************************************************************************************************
******************** 18 mei 2013 11:34 ********************
HikaShop opgevraagd op 18 mei 2013 11:34
******************************************************************************************************************************************************
******************** 18 mei 2013 11:35 ********************
HikaShop opgevraagd op 18 mei 2013 11:35
******************************************************************************************************************************************************
******************** 25 mei 2013 17:43 ********************
HikaShop opgevraagd op 25 mei 2013 17:43
---- Details ----
Wisselkoersen succesvol bijgewerkt
******************************************************************************************************************************************************
******************** 25 mei 2013 17:45 ********************
HikaShop opgevraagd op 25 mei 2013 17:45
******************************************************************************************************************************************************
******************** 25 mei 2013 17:46 ********************
HikaShop opgevraagd op 25 mei 2013 17:46
******************************************************************************************************************************************************
******************** 25 mei 2013 17:47 ********************
HikaShop opgevraagd op 25 mei 2013 17:47
So after 18 mei 2013 11:33, there are no "Orders checked" entries anymore.
In the new file, that was just created, this line is also missing.
I have some old orders still with a status of 'created', that are older than 10 days. I expect them to be put on 'cancelled', but it still does not work.
Maurice
P.S.: The unix timestamp in the order cancel plugin, that tells the last time the plugin was called, is still the same.
So it appears the cron job itself is called correctly, but it doesn't call this plugin anymore.