Errer is a french first group verb. So it follow the regular conjugation pattern of the first group like: aimer. Follow this link to see all the endings of the conjugation of the first group verbs : conjugation rules and endings for the first group verbs.
Errer is conjugated the same way that verbs that end in :
-er. First group verbs always end with
as their infinitive. Endings of first group verbs are regular.
Note : Although endings are perfectly regular, spelling changes occur in the stems of verbs in
and similar verbs.