Please be aware the latest version of EbizMarts SagePay is needed in order to rectify this issue.
There are a number of conflicts between the EbizMarts SagePay extensions and our invoicing extension.
We have release a special version of the invoicing extension which compensates for this which is now available on the website when you purchase.
You may see issues such as no order information being displayed or problems viewing your payment methods.
Before you install the modified extension you must make a change to the EbizMarts config.xml file (app/code/local/EbizMarts/SagePay/etc), the change you make is dependant on which version you use:
SagePay Direct Pro:
<!-- Commented out by webshopapps <order_invoice>Ebizmarts_SagePayDirectPro_Model_Sales_Order_Invoice</order_invoice> -->
<!-- Commented out by webshopapps <info>Ebizmarts_SagePayServer_Block_Payment_Info</info>-->
SagePay Pro: Both of the above.
This occurs if you tell the extension to print something like labels or a PPI image but you don't enter where to print them or the data you've input is invalid as it's not numeric. It could also occur with fields such as the font size, margin or dimensions for the logo.
This type of configuration will cause the error, you're telling the extension to include a shipping label but have wiped out the default X value that is pre-populated on install.