I run several tests again - but without success at the end

But the whole story...
The availble patch has been applied.
I have several different seed files for diferent locations but just one nedi.conf. I tried to optimize the sequence of the userid - password list in nedi.conf and I got better results during the discovery process.
I started again with one specific seed file and with an empty database and the error appears later than before, when the userlist in nedi.conf was not optimized.
Every time I started the discovery process, the error appears several devices later and at the end, all devices of that seedfile are discovered without error.
Than I took the next seedfile and performed the same steps until all devices have been discoverd without errors.
I was happy and I thought, everything would be OK now.
But in real life, I run many discovery processes with different seed files in parallel and then I get the error again (Resource temporarily unavailable at /var/nedi/inc/libcli-iopty.pm line 927.)
The time nedi requires for a discovery of all devices of all locations one after another would be more than 24 hrs - but I would like to discover each location at least once a day...
But because of this problem, some locations are not completely discovered at all...
In addition, I receive the following error during the discovery process:
Use of uninitialized value in concatenation (.) or string at /var/nedi/inc/libsnmp.pm line 292.
Do you have any additional hint?