Thanks, HD.

I think at 184", this pdf at 150 dpi (the background is a bitmap) is around 27k px.

But yes, one can get that infernal error message. Most times on large format work I've done in an Xara application, the error pops up after the pdf has been produced so in that sense it is non-fatal. There are ways to mitigate XP&GD's error. That is choping up such a full background into 2 or more pieces. This help to ease the strain. (For fun, I've made one the same size in Affinity Designer. Its export took 45 minutes...)

Click image for larger version. 

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