P/T ContactForm Retrieving Custom fields Value after submitting form
In Craft 2.5 with Contact Form 1.4 I'm receiving the same error when using:

{% if message is defined %}{{ message.contactTel }}{% endif %}


I've gotten around this by using the Craft Request method getPost which can return a post value from an array. In the case of the original question, the following should work:

&lt;label for="fromCompany"&gt;Company:&lt;/label&gt;
&lt;input id="fromCompany" type="text" name="message[fromCompany]" value="{% if message is defined %}{{ craft.request.getPost('message.fromCompany') }}{% endif %}"&gt;