There are three stages to resolving this issue, which need to be done in order.
Check that the approver has approvers assigned
Log in to FocalPoint Administrator.
Click System Control, Security Profiles.
On the appropriate profile, click Members
Find the person approving
Click Approvers
Select the appropriate module
Make sure there are users listed.
Check the approvers have access and an appropriate sign-off limit
Log in to FocalPoint Administrator.
Click System Options, Purchasing, Purchase Request Setup.
On the purchase request type getting the above error, click Usage
Make sure the approvers are active and have a sign off limit higher than the purchase request.
Check approvers have permission to approve Purchase Requests
Log in to FocalPoint Administrator.
Click System Control, Security Profiles.
Edit the profile the approver is in
On the Security tab, click Authorisation
Select the Purchase Request checkbox.