"Vectorworks cannot be run if one or more active monitors are set to 256 color mode. Please check your monitor settings."
This can be resolved by deleting the "HP RC Mirror Driver". To do so, follow the steps below.
Click on Start
Right-click on Computer to the right (My Computer on XP) then left-click on Properties
Click on Device Manager to the upper left-hand side of the screen (on XP click on the Drivers tab and then Device Manager)
Expand Display Adaptors in the list
Right-click HP RC Mirror Driver and select Uninstall , and select Delete the driver software for this device (if present).
Note: These drivers are used for a remote connection with HP support. If you wish not to delete the driver you do also have the option of right-clicking and selecting Disable.