I just installed another theme and had the same result, this time I saved the error message:
Installing the theme…
Theme installed successfully.
Warning: fopen(/home1/spiremar/public_html/realmailflyers/wp-content/themes/simplewhite/style.css) [function.fopen]: failed to open stream: No such file or directory in /home1/spiremar/public_html/realmailflyers/wp-includes/functions.php on line 4284
Warning: fread(): supplied argument is not a valid stream resource in /home1/spiremar/public_html/realmailflyers/wp-includes/functions.php on line 4287
Warning: fclose(): supplied argument is not a valid stream resource in /home1/spiremar/public_html/realmailflyers/wp-includes/functions.php on line 4290
