Following error is coming up when try to create recurring invoice after setting up the template.
APP-SQLAP-10000: ORA-04062: signature of package "APPS.AP_ETAX_PKG" has been changed occurred in
Get_Quote<-Calculate_Tax<-Post-Query<-CREATE_REC_INV
with parameters (&PARAMETERS)
while performing the following operation:
Calling Payables eBTax API
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FRM-40735: POST-QUERY trigger raised unhandled exception ORA-20002.

Sorry for the late reply as I was away from the forum for a longer time.
About your inquiry, looks like you have invalid objects in the database. You can compile the invalid objects by launching adadmin utility at the back end. That should fix this issue.