HTTP step failing with "Out of memory"

[DuncanL]

For some reason an HTTP step (doing a secure GET to a file) in our build has started failing every night with:

Error getting file: Out of memory (OK)

The machine has over 400Gb of disk space and 3Gb of RAM. It's doing nothing else except running VBP 6.7a.

Any suggestions? It's been fine for weeks and now fails every time. Is there any way to get more verbose logging?