Does a Durable Power of Attorney give me the right to file a motion in court on my daughters behalf?

I have a Durable Power of Attorney for my daughter. She was being sued for custody of her son while she is incarcerated. She wanted to get a continuance for the hearing until she is released in 2 weeks so that she may retain legal counsel. I filed the motion for her with the power of attorney. The judge told me that was not legal and that it is my daughters fault she hasn't been able to get an attorney because she's in jail. Is what I did illegal? Isn't my daughter entitled to prepare a defense and file an answer to this petition even though she is incarcerated. Especially since she is to be released in 2 weeks.