Tab redirect onclick after options saved

I have a plugin that has tabs in the admin with a form on the first tab. The second tab is hidden until information is saved into the form on the first tab. I want the button in the form to redirect the user to the second tab onclick after the options are saved. Using wp_safe_redirect and getting an error – Cannot modify header information. Have tried all the necessary things to make this go away, like removing spaces before the opening and closing PHP statement, adding ob_start, and ob_end_flush. No go. Have messed around with this for a couple weeks. Tried JavaScript and a few other tricks that haven’t worked. Please help!

Here’s my code below:

//checks for active tab and replaces key with the related settings key. Uses the plugin_options_tabs method to render the tabs.
	function plugin_options_page() {
		echo '<link type="text/css" rel="stylesheet" href="' .plugins_url( 'css/spreview.css' , (__FILE__) ). '" />';
		$tab = isset( $_GET['tab'] ) ? $_GET['tab'] : $this->locate_listing_key;
		if ($tab == $this->locate_listing_key) {
		?>
		<div class="sprwrap">
			<?php $this->plugin_options_tabs(); ?>
			<form method="post" action="options.php">
				<?php wp_nonce_field( 'update-options' ); ?>
				<?php settings_fields( $tab ); ?>
				<?php do_settings_sections( $tab ); ?>
				<input type="submit" name="submit" value="<?php _e('Find It') ?>" class="button-primary" />
               <?php $myadminurl = admin_url();
		$redirect_to = $myadminurl . 'admin.php?page=spr_plugin_options&tab=select_listing'; ?>
                </form>
		<?php ob_start();
			global $wp_version;
		if ( version_compare( $wp_version, '3.4.0', '>=' ) ) {
			if ((isset($_GET['updated']) && $_GET['updated'] == 'true') || (isset($_GET['settings-updated']) && $_GET['settings-updated'] == 'true')) {
       			$location = empty($redirect_to) ? get_redirect_link() : $redirect_to;
       			wp_safe_redirect($location);
       			exit;
    		} //end of updated true
		}
		ob_end_flush(); ?>
        </div>
        <div class="sprwrapright">
        <?php spreview_sidebar_one() ?>
        </div><div class="clear"></div>
		<?php } else if ($tab == $this->select_listing_key) {
			?>
			<div class="sprwrap">
				<?php $this->plugin_options_tabs(); ?>
				<?php //settings_fields( $tab ); ?>
				<?php do_settings_sections( $tab ); ?>
                <?php include 'superpages-reviews-listings.php'; ?>
			</div>
            <div class="sprwrapright">
        	<?php spreview_sidebar_two() ?>
        	</div><div class="clear"></div>
		<?php }
	}