I have been working with a company for about 6 months, with the job title of software engineer/support specialist. So far, I have done very little software work, but that was initially expected.
The problem is with my boss, the owner of the company. I'm expected to support their software to corporate customers with very little assistance. The previous support employee left several months before I started, and the only other person able to help me is doing field work 90% of the time. He is unreachable almost all of the time when he's doing field work.
My boss tells me to "jump into the thick of it and get my hands dirty" to learn the software. If a customer contacts me, I'm supposed to learn as I go to fix it. I had no problem doing this, but a couple weeks ago, I made a change that broke the customer's systems for 4 days. Eventually the field guy had to fix it when he had time. Now just two days ago, the system broke again even after I was being very careful. The boss is blaming me when I feel I haven't had the resources to succeed. He mentioned to me that "this system has been working for years and is now breaking", implying that I'm the cause.
Another issue is that I have a couple of actual software projects that I haven't had any chance to start. The customers are waiting for work to be completed, but I just haven't had time due to my support load. I probably would have time if I was more knowledgeable of the software, but even after 6 months I'm not up to speed with how to fix things quickly.
How should I handle this? Should I bring it up to my boss and what should I say? He's very headstrong.