Directory /opt/projeqtor/files/attach/ does not exist or php user (www-data) has not write right to this folder.

The folders are existing and www-data has access rights as well.

Check security tool such as Selinux that may block acces to directory.

SELinux is not installed in my ubuntu system. 

Can you try without the ending "/"

Hi,

Sorry for the delayed response. 
I tried and noticed that even then I am not successful. But I noticede that I did not get wrong message for documents folder. Incorrect messages are showing for attachments, logs and parameter file configuration. 

Thanks & Regards,
Kishore 

Hi,

I'm sure it is some security on server level that blocks.

Did you try :

su - www-data
cd /opt/projeqtor/files/config
echo "TEST" > test.log

Based on my understnding we can't switch to the user to "www-data" using 'su" command, the reason being there shall not be password set for "www-data" at default. But if I forcefully set, I doubt any web application would work smoothly. Please clarify. 

Thanks,
Kishore

Idea is to really connect as www-data to verify it thie user can really write on that directories

Ok, Whilst I am figuring out the access permissions, I would like to know is there any limitation set for the length of the characters, or  number of folder limations for these paths? 

Regards,
Kishore 

No, no limitation.
Just take care to avoid special characters that would not be supported by the system . Keep it simple (use only ASCII characters to be sure)