After many hours of study…. I have found the Solution! :)
In the string of the cforms_settings, there are many string fields the coming as:
… s:nn:"string";s:nn:"another string"; …
where:
s: define a string field
nn: define the length of the string
So, for each form created, there are some string that contain the absolute path of the plugin. If I change the server, or I change the subdomain, the absolute path and his length changes too.
For example:
If I have a wordpress site in a server with path:
/var/www/vhosts/demosite.org/httpdocs
and I will move all to another server with this path:
/username/newsite.eu/public_html
the lenght of this path change. So, there are other strings similar in the configuration string that change too. So, what we need to do is:
1. Change all string about web address of the site, absolute path of the server, etc.
2. Calculate the new length of this string
3. Change the value of the length of the string
Example:
s:66:"/var/www/vhosts/demosite.org/httpdocs/wp-content/plugins/cforms$#$"
s:61:"/username/newsite.eu/public_html/wp-content/plugins/cforms$#$"
This modify will apply of ALL strings in relation of web address ("http://www.demosite.org/…") and absolute path, as in the example.
I wish this can help someone.