<apex:page Controller="PaypalProccessor" >
<!-- Page Header -->
<apex:sectionHeader title="Pay With PayPal" subtitle="Safe hai" />
<!-- Begin Form -->
<apex:form >
<apex:pageBlock title="Enter Details" mode="edit" >
<!-- Fields -->
<apex:pageBlockSection columns="3" showHeader="true" title="Membership Status" >
<apex:inputField value="{!firstName}" required="true" />
<apex:inputField value="{!lastName}" required="true" />
<apex:inputField value="{!Addy1}" required="true" />
<apex:inputField value="{!Addy2}" />
<apex:inputField value="{!CardNo}" required="true" />
<apex:inputField value="{!expMo}" required="true" />
<apex:inputField value="{!expYe}" required="true" />
</apex:pageBlockSection>
<!-- Button Section -->
<apex:pageBlockButtons location="bottom">
<apex:commandButton value="Submit" action="{!doDirectPayment}" />
</apex:pageBlockButtons>
</apex:pageBlock>
</apex:form>
</apex:page>
What I am doing wrong? It is giving me this error Could not resolve the entity from value binding '{!firstName}'. can only be used with SObjects, or objects that are Visualforce field component resolvable.