I transferred my character from a Legacy to Non-Legacy world and didn't have any problems; I went over the checklist before doing and I was never in a Free Company though I was in a Linkshell which didn't seem to cause any problems.

I did my transfer on March 1st @ 3am EST, just after Legacy transfers opened and expected to have issues but it went surprisingly well and my character was transferred over within a few minutes tops.

If you meet all the requirements I can only assume it either has to do with the World either being full or too many transfers being done at that time.