This error means that the user is not allowed to approve the affected transaction, there can be a couple of different reasons as to why this might be.
First of all, please ensure that the transaction has not already been approved, as if it has, this error message is correct to appear. You can check if it has been approved, by finding the Purchase Request, highlighting it and clicking "History".
If the transaction has definitely not been approved, then the user may not have usage permissions to the Purchase Request type. To resolve this, follow these steps:
Log in to FocalPoint Administrator
Click System Options, Purchasing, Purchase Requests Setup.
Select the relevant Purchase Request Type
Click Usage
Ensure that the affected user has a tick in the "Active" column
Click OK to save
If they have permission to the Purchase Request type itself, then the issue may be that they don't have permission to approve. To resolve this:
Log in to FocalPoint Administrator.
Click System Control, Security Profiles
Highlight the profile that the affected user is in and click Edit
Click onto the Security tab
Expand Authorisation by double clicking on it
Ensure that Purchase Requests has a green tick beside it (you can change this to a red cross and vice versa by double clicking on it)
Click OK to save