You can avoid problems one of two ways.
First update to the new 6.22 beta which covers SMP and nonSMP rigs. The flag -smp is necessary to get smp units. Go here to learn more:
Folding Forum • View topic - Windows SMP v6.22beta2 client released!
Second, you can get the extended 5.91 or 5.92. The only change is in the expiration date. Go here to get it:
Folding Forum • View topic - 5.91 and 5.92 deprecated but extended
All methods can use the file drop in method and relink to get them to work... Just make sure you back up first.... I lost about 3000 points this weekend sorting this mess out.