I want to understand whether Smart Contracts & Ethereum can be used to achieve the functionality of our current VB6 ERP application where we have concurrent users creating new transactions, editing/deleting existing transactions and have reports to view saved transactions. Can Smart Contracts/Ethereum be a platform of choice for such applications
Blockchains are, in theory, immutable. Once you have data in there nobody can take it out. Therefore also Ethereum transaction are immutable - they can't be modified or deleted. There is a small exception to this which does not make a difference here but I'll blurt it out: chain reorganizations (reaching consensus) may delete some blocks with transaction, but those transactions will be reprocessed in another block.
However, blockchains (and Ethereum) are very good in concurrency. Multiple users can read and write and the Ethereum can reach consensus about in which order the transactions should appear in the canonical (final) chain. Also viewing is very easy - all data which was ever input into the blockchain is visiable forever for everyone.
Therefore Ethereum is not suited for CRUD operations, and no blockchain is.
As the previous comment states, blockchain is not designed for CRUD operations, but... I believe there is a provocative idea here. An ERP performs many functions, but one could abstract its architecture as made of a few major building blocks: master data, transaction records, reporting, planning, and so on. One of the ERP initial - and still most important - use cases is to be the "system or records" for a collection of business processes (e.g. inventory management, procurement, sales etc.). And this happens to be a perfect use case for blockchain: storing in an secure way the records of processed transactions along a timeline. One "blockchain-enabled-ERP" would still have to use regular databases for other functions, like planning, and reporting, but I'd argue that with the emergence of IoT, moving the records into the blockchain is the inevitable right direction.