what kind of errors?

For some errors, it can not be corrected. I-140 application must match
info on LC (perm application). If the same errors occurred on your LC.
It is better not to correct them on I-140. If in this case, your lawyer
may correct it after USCIS asking for confusion or something. What your
lawyer should do is to explain such as typos or something.

If things are not critical, your lawyer may be right because mis-matched LC and I-140 is even worse.