So in the business that I work at there is a programmer who worked abroad and "finished" our salesforce account. I have been given complete access to the account and was given the task of adding a copy function for addresses and implementing an inventory management system. I finished the copy function, which copies customer's addresses onto the user's clipboard and it works fine on my salesforce account but when I try to add it into the sandbox of the business's account I cannot even touch the code. As soon as I add anything, it will say deployment failed.

The visualforce page is called shippinglist and when I try adding my code, immediately it says deployment failed. I don't even save and it says deployment failed. The error is: deployment failed shipping-detail,: managing installed classes failed to install. I also tried to make my own visualforce page with his code but then one of the extensions is not linked. What could be the problem?
 

So in the business that I work at there is a programmer who worked abroad and "finished" our salesforce account. I have been given complete access to the account and was given the task of adding a copy function for addresses and implementing an inventory management system. I finished the copy function, which copies customer's addresses onto the user's clipboard and it works fine on my salesforce account but when I try to add it into the sandbox of the business's account I cannot even touch the code. As soon as I add anything, it will say deployment failed.

The visualforce page is called shippinglist and when I try adding my code, immediately it says deployment failed. I don't even save and it says deployment failed. The error is: deployment failed shipping-detail,: managing installed classes failed to install. I also tried to make my own visualforce page with his code but then one of the extensions is not linked. What could be the problem?

Currently, I am trying to make a copy function for a textbox. In the textbox should be the address in a specific format because that is the format that USPS needs to ship a product using USPS. The textbox/output field should have what is displayed under Account Summary and over Opportunity information in my code. In order for something to even appear though you need to type &id=XXXXX at the end of the page. This is till just a prototype before I integrate the code into the real salesforce account. Does anyone know how I would do this. 

Below is my code
<apex:page sidebar="false" standardController="Account">
    

    <apex:pageBlock title="Account Summary">
        <apex:pageBlockSection >
            {! Account.Name } <br/>
            {! Account.BillingStreet } <br/>

            {! Account.BillingState } 
            {! Account.BillingPostalCode }<br/>
            
            
        </apex:pageBlockSection>

        <script>
 
function copyfieldvalue(e, id){
    var field = document.getElementById(id)
    field.focus()
    field.setSelectionRange(0, field.value.length)
    var copysuccess = copySelectionText()
    if (copysuccess){
        showtooltip(e)
    }
}
 
</script>
        
        <apex:pageBlockSection title="Opportunity Information">
            <apex:outputField value="{!Account.name}"/>
            <apex:outputField value="{!Account.Phone}"/>
            <apex:outputField value="{!Account.BillingState}"/>
        </apex:pageBlockSection>
    </apex:pageBlock>
    
</apex:page>