MineConomy is repeatedly disconnecting from the MySQL server. Since I have re-setup everything from scratch on the new server, there might be some default setting on the new version I am using now that is causing this, but Mineconomy as opposed to other plugins is not automatically reconnecting to the server. So after a while, it simply stops working.
Since Minecononmy was not updated since 1.5.2, I am not sure if the admin is still maintaining it. I sent a bug report, but it seems that the same bug was identified by other users for the last 2 versions already, marked as fixed but we still have the issue.
So what I did now: I wrote a simply plugin that can deal with money since MineConomy was basically only used to see the account status and to give money to users. The only real advantage of having a economy plugin is if other plugins have money functions (such as a shop) but we do not use any external plugins that do that. We wrote all money-related plugins ourselves. So in the end we got rid of another plugin by writing some lines of code.
The new commands are now /money status and /money give <user> <amount>. There is a appropriate help in the system and on the website.
Thanks for all the hard work Unco!! :D
thanks unc! :)