BBCode Guide is untranslatable: disallowed HTML

Hi!

I've tried to translate this module into Russian but there's a problem I couldn't solve — all strings you can find there are translatable except the biggest one (BBCode Guide) which was skipped because "... it contains disallowed HTML". I tried to import that string manually only to see "The submitted string contains disallowed HTML" error occured. I thought there were misspellings I've made and did the new translation of this so-called "string" (>12K with spaces!) from scratch again... and again with all mark-up copied from source but the problem is still here — "The submitted string contains disallowed HTML". I don't know what to do. Please help me to help you with my translations.

PS My current root.po attached below.