Hi
I need your help for this problem
You are probably using a field EC05 inside a label or relevance or any other calculation, but EC05 is inside a repeat group and the other field is not.
This error message is really not great. The challenge is that it can happen in a lot of different contexts needing different action so for now we've left it pretty raw.
I can see from the [2] after children_per_caregiver that children_per_caregiver is a repeat. As @MehrabAli says, you have an expression that uses ${EC05} in a relevant expression for the IC field which is outside the children_per_caregiver repeat.
When ${EC05} is used inside children_per_caregiver, it means the value for ${EC05} for the current repeat instance. If it's used outside like in your form, it means all the values for all the repeat instances which can't be used in your relevant expression.
This could mean IC is in the wrong place, you want to join the values of ${EC05} in some way, or any number of other things. If this description of the error doesn't give you enough information to resolve the issue, please tell us more about the structure of your form and what you're trying to achieve. If you can share the full XLSForm that would be most helpful.