[docs] rename perm level error article

erpnext/docs/user/manual/en/customize-erpnext/articles/perm-level-error-in-permission-manager.md

@@ -0,0 +1,19 @@
+<h1>Perm Level Error in Permission Manager</h1>
+
+While customizing rules in the [Permission Manager](https://erpnext.com/user-guide/setting-up/permissions/role-based-permissions), you might receive an error message saying:
+
+`For System Manager_ (or other role) _at level 2_ (or other level) _in Customer_ (or document) _in row 8: Permission at level 0 must be set before higher levels are set`.
+
+Error message indicates problem in the existing permission setting for this document.
+
+For any role, before assigning permission at Perm Level 1, 2, permission at Perm Level 0 must be assigned. Error message says that System Manager has been assigned permission at Perm Level 1 and 2, but not at level 0. You should first correct the permission for System Manager's role by:
+
+- Assigning permission to System Manager at level 0.
+
+Or
+
+- By removing permission at level 1 and 2.
+
+After executing one of the above step, you should try adding additional rules in the Role Permission Manager.
+
+<!-- markdown -->