Administration - Installation - Core: htaccess-Redirection of old links

I have some old weblinks in Ilias that for some reason have a new permalink now and I can't figure out how to write the proper htaccess redirection rule. I tried different methods, none of which did the job so far. Currently my .htaccess starts like this (line #3 contains my problematic link):

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<IfModule mod_rewrite.c>
        RewriteEngine On
        RewriteRule ^goto.php?target=webr_1012 /goto_clientname_webr_6598.html
...
        RewriteCond %{QUERY_STRING}  ^lang=([^=]*)$
        RewriteRule ^goto_(.*)_(wiki_([0-9]+|wpage)(.*)).html$ goto.php?client_id=$1&target=$2&lang=%1 [L]
        RewriteRule ^goto_(.*)_(wiki_([0-9]+|wpage)(.*)).html$ goto.php?client_id=$1&target=$2 [L]
        RewriteRule ^([^\/]*)_user_(.*)$ goto.php?client_id=$1&target=usr_n$2 [L]
        RewriteCond %{QUERY_STRING}  ^lang=([^=]*)$
        RewriteRule ^goto_(.*)_([a-z]+_[0-9]+(.*)).html$ goto.php?client_id=$1&target=$2&lang=%1 [L]
        RewriteRule ^goto_(.*)_([a-z]+_[0-9]+(.*)).html$ goto.php?client_id=$1&target=$2 [L]
        RewriteRule ^data/.*/.*/.*/.*/.*$ ./Services/WebAccessChecker/wac.php [L]

...
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When I click on the link containing the pattern ("goto.php?target=webr_1012"), then Ilias seems to understand, where I want to go, but it doesn't redirect me there. Insteads it displays a warning message:

"You are not allowed to access object xyz." (although I do have the access privileges).

Any help appreciated!