>I can't define a memory variable to be more than 255 (or perhaps 254) characters. Yet the docs say that the limit is 16,777,184 chars.
>What am I missing here? Thanks.

From HELP:
Maximum length of a string literal - 255
but you can assign more that that if you use:

x1 = REPLCAITE("X",255)
x1 = x1 + REPLCAITE("Y",255)
x1 = x1 + REPLCAITE("Z",255)
? x1

or even:

TEXT TO lcVeryLongText NOSHOW TEXTMERGE
     <<REPLICATE("X",8000)>>
ENDTEXT
? lcVeryLongText