Limit of creation variables


I want to know whether is the limit of the creation of variables from /public_html/custom/Extension/modules/Accounts/Ext/Vardefs
Because from 109 variables, i cannot create any new variable. The backoffice return me the white page after repaired.

I checked the db, there is no problem here and i can add as many as variables direct form mysql.

Is there anybody has idea what is the problem, please? Thank your very much and sorry for my poor English.