Getting an error "Too_many_tokens" after created rule relating to Freight

Requirement - Client wants different GL Account for event created relating to Freight and different GL Account for event relating to normal invoice

Actions taken
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1)We have created new event type "Freight"
2)We have used decode script in Unearned Revenue function of Revenue and Invoice Accounts in Autoaccounting
3)We have used PL/SQL function in decode script.
4) We created 3 events for a Project ( All events having event types as Freight)
5) We generated draft Invoice then Approved and Released the Invoice
6) When we transfer Invoice to Receivables we are getting following error message

Error : Too_many_tokns

We have created pl/sql function and called in sql script with decode