MSIR.0680 LONGSTRING error: truncation in line (linenum) procedure (procname), file (fname)

A longstring variable, or $function or method result was used in a context that would result in the longstring being implicitly truncated. The most common examples of this are assignment of a longstring to a shorter, non-longstring variable, and the passing of a longstring longer than 255 bytes to a non-longstring capable $function. One somewhat unusual but confusing case that can produce this error is assignment of a longstring with trailing blanks to an image item with STRIP set (the default). Because STRIP results in the trailing blanks effectively disappearing, this is considered a truncation error.

Longstring truncation issues, and methods for avoiding truncation errors, are covered on the Longstrings page.