I keep getting an Internal Server Error (500) when I copy and paste the text into the .htaccess file. I've modified .htaccess files before so I don't believe it's a text editor problem. I even used the FileManager tool in Plesk to create the file and convert to unix returns but nothing seems to work.

BTW - here's the error log entry:
[Sun Feb 17 17:20:28 2008] [alert] [client 72.185.196.170] /var/www/vhosts/royoart.com/httpdocs/.htaccess: RewriteCond: unknown flag '^'

Which version of Apache do you have?

Version
psa v8.3.0_build83071218.18 os_RedHat el4
OS
Linux 2.6.23.12-ts.grh.mh.i386-vmsp

No, not the linux, the http which version is.
.htaccess is connected to httpd (Apache)

You can see this in PLESK or if you type in shell httpd -v

Sorry, 2.0.52-38.ent

I have the same problem in my server. When I upload .htaccess, have Internal Server Error
PLESK Power Toys 4.6.0
Parallels Plesk Panel version 9.0.1
Server version: Apache/2.2.3

We have a bug in the code.
We will release in a few days a new version, the bug is a [^] in the code
If you remove that, will work.

thanks,
now work correctly, I'm waiting the update
now I'm having a problem with whois, does not appear nothing when I click search, you know how to open port 43? The response of the planet that was:
"There are no firewalls or access control lists on the server. If you need a port open, you must have a program configured to listen on that port. Please let us know if there is anything else that we can help you with."

http://www.yougetsignal.com/tools/open-ports/
Port 43 is closed on 174.133.112.162.

Do you have any solution?

Yes, port 43 should be open.