I am running into the same issue with my favorite FTP program, SmartFTP. This application feature a clipboard monitor, and like all windows programs I have tested with clipboard monitors, it freezes as soon as I copy text in OSX, provided the Parallels "Share Clipboard" feature is turned on.
See the thread here:
http://www.smartftp.com/forums/index.php?/tracker/issue-20-crash-in-parallels/
What the thread does not mention is the hours I spent with their development team debugging this issue, being a software engineer myself we were able to talk tech and trace the problem down to a single line of code. Making the determination that not only were we unable to fix the problem, we were unable to set up any error trap to catch the problem. This issue needs to be addressed by the Parallels Team, as they are the only ones who can fix it.
Feel free to contact me for more technical details of this bug. I will now paste my original description of the bug I sent to SmartFTP.....
How to reproduce the crash:
1. Open SmartFTP
2. Open a new document in Apple's TextEdit app.
3. Type something, then select the text you typed.
2. Press Command+C (Apple Key + C) to copy the text.
3. Watch SmartFTP freeze hopelessly
That's it.... If you use the computers clipboard while SmartFTP is opened, it will crash... and it will also crash the Parallels Tools that synchronize the Windows and Mac clipboards. The only way to get clipboard working again is to reboot windows!
My uneducated guess is that there is some kind of module in SmartFTP that is monitoring the windows clipboard, and it gets in a cat fight with the Parallels clipboard module... and they both lose in the end.