The message is self-explanatory: there wasn't enough RAM available to load the sample library.
This can happen on any system, regardless of specs, if the library's big enough. When it happens, there are usually ways to either reduce the memory footprint of the sample library or to reduce the amount of memory SONAR's using.
For example, an orchestral library may consist of multiple layers of samples, e.g. mid and far microphones. Using only the mid mics cuts RAM usage in half. Sometimes you have a choice of how many round-robins or velocity layers to use. Sometimes you can adjust the ratio of buffered versus streamed data. Sometimes you can purge unused samples. I'm not an EWQL user (dongle alergy) so I can't offer specifics.
If you're trying to use a single EWQL instance for an entire orchestra, you may have to split it into individual sections or instruments with a separate instance of EWQL for each. That will allow you to freeze individual sections/instruments upon completion, freeing the memory they were using.
But if you absolutely need all the instruments to be "live" because you're composing in MIDI, consider using a less-capable sample library for composing and then substitute the better library later for rendering. The TTS-1 is very lightweight so you can have as many instances as needed for composing. If external hardware modules are an option, that's even better (my own preferred solution).
Some heavyweight orchestral composers go as far as running sample libraries on separate computers. You can even create a "farm" of multiple computers and have an unlimited real-time instruments. If you're Hans Zimmer or Danny Elfman you can afford to do that. We mortals have to be more imaginative.