Thank you for taking the time to report this issue to the Community, although I apologize that you have not yet received a response.
If you are still experiencing this trouble, can you provide some more details?
What version of Quicken you are currently running? This can be found under Help > About Quicken. What type of transaction are you trying to create? Are you entering the transaction directly into the register or are you using the "Enter Transactions" option?
The more information you can provide regarding this issue will help the Community to better understand and assist.