This seems like a memory allocation error.
See: VirtualAlloc MEM_COMMIT and MEM_RESERVE
Pandoc may use rather large amount of memory for conversion.
See also Pandoc's FAQ:
Pandoc sometimes uses too much memory. How can I limit the memory used by pandoc?
pandoc +RTS -M30m -RTS
will limit heap memory to 30MB. When converting a document requires more than this, an out of memory error will be issued.
The error message reports the limitation of your page file:
The paging file is too small for this operation to complete.
Can you increase the page file size?