Howdy! I've been trying to search for weeks on a topic that hasn't been posted in the forum (or maybe i'm just bad with the forum searchengine hahah). Anyways, I need help with contacting medium sized businesses about a software program. Here's the background story. (Registered just so I could ask this hahaha, i've been procrastinating too long anyways on joining the site

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It's a really spiffy customizable database software management program that handles several tasks from transaction systems (such as supporting membership fees, commissions, etc.) to geneealogy tracking, self replicating web sites, graphical reporting, phpbb forums, and so forth.
In my opinion, not being a computer junkie at all, the software sounds revolutionary and will drastically improve the performance of any company. Before taking on this software as a marketing project of mine, I asked former clients in the past who've used the software and they all said it was as good as it sounds.
Now, here's the problem...
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I've never done this type of marketing before. This isn't the type of marketing that appeals to the common man; this product is meant specifically for large businesses that have multiple online software programs that it relies on to run several million pieces of information. To trust a relatively new software with such important information will be hard to advertise.
So far what I have is a Viral Marketing strategy that involves current users spreading how useful the software is. Problem with that is, at that rate, it will never reach big business (and big profit) and never live up to its potential.
Second problem is, the company that contracted me for this is based in Europe and will only accept Euros as payment. Should I push to reverse this and accept dollars also or leave their policy?
Third problem is, I have no idea how to approach a medium/large scale business and say "trust your millions of pieces of information with this software". I mean, what department do I even email for that type of stuff? Hahahahah.
I'm excited because my business podcast has led to this client (which off topic, podcast is a very great way of marketing and promoting yourself for free or little cost) but now i'm at a point where I need help from the real Gods of Marketing hahaha.
Not sure if i'm allowed to go in-depth about the software due to site policy and spamming. What do I do? I'm entering the big leagues of marketing with millions of dollars at stake and it's a lot different than what i've been successful with thusfar.