place validation error messages in a separate page

Not that I know of. How about styling the validation errors to make them fit into your form space? Can you post a link to your page with the form on it?

With that limited amount of space, you probably want to turn off most of the default error notification. Try something like this to start:

[css]
body #gform_wrapper_1 .validation_error,
body #gform_wrapper_1 li.gfield.gfield_error .gfield_description.validation_message {
	display:none
}

body #gform_wrapper_1 li.gfield.gfield_error {
	padding:2px!important;
	border:none
}

body #gform_wrapper_1 li.gfield.gfield_error input {
    background: red;
    color: #fff;
}

Here's a screenshot http://bit.ly/nExWry

There will be more tweaking to do based on how you want it to look, but hopefully this will get you started. Please post if you need additional help.