Long list of taxonomy terms input problem

Help appreciated (it may be that'd I'm approaching this the wrong way, or that I'm hitting a limitation on the correct method... whichever it is I'd like to know)

I have many nodes in one content type (referencing websites). They have a field (term reference) that puts the domain name e.g. google.com into a taxonomy vocabulary as term... which so far works great. When I'm looking at a node of this content type I can see a list of other nodes referencing the same domain name... all good..

Now i need a second content type (companies) that has a field (term reference) that references the same vocabulary, but I've hit a snag. I want one node (e.g. one about google.inc) to have entries in the term reference for each of it's domain names.... which looks like it'd work, but using this example google has 247 domain names, and if I try to paste them all in to the term reference field I get an error (see below at the bottom)... this I think is because I'm trying to insert a string thats too long for the field to cope with (note the "go" at the end where the string has been cut off...

you could easily reproduce this problem by creating a term reference and attempting to paste in this list.

here's the list:

1e100.net, 466453.com, adsense.com, adwords.com, android.com, blogger.com, blogspot.com, chromium.org, doubleclick.com, feedburner.com, froogle.com, g.cn, g.co, ggpht.com, gmail.com, gogle.com, gogole.com, goo.gl, googel.com, googil.com, google-analytics.com, google.ac, google.ad, google.ae, google.al, google.am, google.as, google.at, google.az, google.ba, google.be, google.bf, google.bg, google.bi, google.bj, google.bs, google.bt, google.by, google.ca, google.cat, google.cc, google.cd, google.cf, google.cg, google.ch, google.ci, google.cl, google.cm, google.cn, google.co.ao, google.co.bw, google.co.ck, google.co.cr, google.co.id, google.co.il, google.co.in, google.co.jp, google.co.ke, google.co.kr, google.co.ls, google.co.ma, google.co.mz, google.co.nz, google.co.th, google.co.tz, google.co.ug, google.co.uk, google.co.uz, google.co.ve, google.co.vi, google.co.za, google.co.zm, google.co.zw, google.com, google.com.af, google.com.ag, google.com.ai, google.com.ar, google.com.au, google.com.bd, google.com.bh, google.com.bn, google.com.bo, google.com.br, google.com.bz, google.com.co, google.com.cu, google.com.cy, google.com.do, google.com.ec, google.com.eg, google.com.et, google.com.fj, google.com.gh, google.com.gi, google.com.gt, google.com.hk, google.com.jm, google.com.kh, google.com.kw, google.com.lb, google.com.lc, google.com.ly, google.com.mm, google.com.mt, google.com.mx, google.com.my, google.com.na, google.com.nf, google.com.ng, google.com.ni, google.com.np, google.com.om, google.com.pa, google.com.pe, google.com.pg, google.com.ph, google.com.pk, google.com.pr, google.com.py, google.com.qa, google.com.sa, google.com.sb, google.com.sg, google.com.sl, google.com.sv, google.com.tj, google.com.tn, google.com.tr, google.com.tw, google.com.ua, google.com.uy, google.com.vc, google.com.vn, google.cv, google.cz, google.de, google.dj, google.dk, google.dm, google.dz, google.ee, google.es, google.fi, google.fm, google.fr, google.ga, google.ge, google.gf, google.gg, google.gl, google.gm, google.gp, google.gr, google.gy, google.hn, google.hr, google.ht, google.hu, google.ie, google.im, google.io, google.iq, google.ir, google.is, google.it, google.je, google.jo, google.kg, google.ki, google.kz, google.la, google.li, google.lk, google.lt, google.lu, google.lv, google.md, google.me, google.mg, google.mk, google.ml, google.mn, google.ms, google.mu, google.mv, google.mw, google.ne, google.net, google.nl, google.no, google.nr, google.nu, google.org, google.pl, google.pn, google.ps, google.pt, google.ro, google.rs, google.ru, google.rw, google.sc, google.se, google.sh, google.si, google.sk, google.sm, google.sn, google.so, google.st, google.td, google.tg, google.tk, google.tl, google.tm, google.tn, google.to, google.tt, google.us, google.vg, google.vu, google.ws, google.xxx, googleapis.com, googleapps.com, googlebot.com, googlecommerce.com, googledrive.com, googleratings.com, googlesyndication.com, googleusercontent.com, googlr.com, goolge.com, gooogle.com, gstatic.com, gtempaccount.com, igoogle.com, keyhole.com, like.com, panoramio.com, picasa.com, urchin.com, waze.com, youtu.be, youtube.com, youtubeeducation.com

and here's the error:

An AJAX HTTP error occurred.
HTTP Result Code: 403
Debugging information follows.
Path: http://ftwv1/taxonomy/autocomplete/field_report_base_url
StatusText: Forbidden
ResponseText:
403 Forbidden
Forbidden
You don't have permission to access /taxonomy/autocomplete/field_report_base_url/1e100.net, 466453.com, adsense.com, adwords.com, android.com, blogger.com, blogspot.com, chromium.org, doubleclick.com, feedburner.com, froogle.com, g.cn, g.co, ggpht.com, gmail.com, gogle.com, gogole.com, goo.gl, googel.com, googil.com, google-analytics.com, google.ac, google.ad, google.ae, google.al, google.am, google.as, google.at, google.az, google.ba, google.be, google.bf, google.bg, google.bi, google.bj, google.bs, google.bt, google.by, google.ca, google.cat, google.cc, google.cd, google.cf, google.cg, google.ch, google.ci, google.cl, google.cm, google.cn, google.co.ao, google.co.bw, google.co.ck, google.co.cr, google.co.id, google.co.il, google.co.in, google.co.jp, google.co.ke, google.co.kr, google.co.ls, google.co.ma, google.co.mz, google.co.nz, google.co.th, google.co.tz, google.co.ug, google.co.uk, google.co.uz, google.co.ve, google.co.vi, google.co.za, google.co.zm, google.co.zw, google.com, google.com.af, google.com.ag, google.com.ai, google.com.ar, google.com.au, google.com.bd, google.com.bh, go
on this server.